21 April 2018:
    * Changed installation procedure. NLopt source code is now part of nloptr package and not downloaded separately during configure in Unix systems in case NLopt library cannot be found.
    * Registered NLopt C functions to be used by external R package and included C API.
    * Documentation is generated using roxygen.

25 September 2017:
    * Fixed a bug in auglag. BOBYQA is now allowed as local solver (thanks to Léo Belzile).

22 August 2016, version 1.1.0:
    * Fixed a bug that sometimes caused segmentation faults due to an unitialized vector of tolerances for the inequality and/or equality constraints (thanks to Florian Schwendinger).

22 March 2015, version 1.0.9:
    * When the problem fails with error status 6 (NLOPT_MAXTIME_REACHED) and maxtime was not set to a positive number in the options, then nloptr tries a couple more times to solve the problem. This is a new approach that should solve the bug that NLopt sometimes exits a problem stating the maximum available time has been reached, even when no limit on the time has been set.
    * Changed warning to message in order to show that for consistency with the rest of the package the inequality sign in the functions auglag, cobyla, isres, mma, and slsqp will be switched from >= to <= in a future nloptr version.

22 February 2015, version 1.0.8:
    * Changed description in DESCRIPTION such that it does not start with the package name (as requested by CRAN).

14 February 2015, version 1.0.7:
    * Changed title field in DESCRIPTION to title case (as requested by CRAN).
    * Added donttest around example in mma documentation.

8 February 2015, version 1.0.6:
    * Updated description to better reflect installation procedure on Linux when NLopt is pre-installed (as requested by CRAN).

28 January 2015, version 1.0.5:
    * Added non-exported functions CFlags and LdFlags to be used in packages that want to link to the NLopt C library.
    * For consistency with the rest of the package the inequality sign in the functions auglag, cobyla, isres, mma, and slsqp will be switched from >= to <= in the next nloptr version. The current version of nloptr shows a warning when using these functions with inequality constraints. This warning can be turned off with options('nloptr.show.inequality.warning' = FALSE).

02 August 2014, version 1.0.4:
    * Increased version number to re-submit package to CRAN with CRLF line endings removed for configure and configure.ac.

25 July 2014, version 1.0.3:
    * Changed NLOPT_VERSION to 2.4.2 for Linux.
    * Changed nloptr.default.options from a data.frame to a function returning the data.frame.

25 July 2014, version 1.0.2:
    * Added configure script which tests for a system NLopt library via pkg-config and uses it if it is sufficiently recent (ie 2.4.*), and otherwise configure downloads, patches and builds the NLopt sources just how src/Makevars used to (thanks to Dirk Eddelbuettel).

05 May 2014, version 1.0.1:
* All unit tests are now enabled and use the package testthat. Install the package with argument INSTALL_opt = "--install-tests" supplied to install.packages to install the tests. The tests can be run after installation with test_package('nloptr'). The testthat package needs to be installed and loaded to be able to run the tests.
    * Changed default value for maxtime option from 0.0 to -1.0. In some cases nloptr returned NLOPT_MAXTIME_REACHED without running any iterations with the default setting. This change solves this.
    * Replaced cat by message or warning. Messages can be suppressed by suppressMessages.

27 January 2014, version 1.0.0:
    * Merged wrappers from the 'nloptwrap' package.

19 November 2013, version 0.9.6:
    * Added a line in Makevars to replace some code in NLopt to fix compilation on Solaris as requested by Brian Ripley.

12 November 2013, version 0.9.5:
    * Updated references from NLopt version 2.3 to NLopt version 2.4 in installation instructions in INSTALL.windows.
    * Added a line in Makevars that replaces some code related to type-casting in NLopt-2.4/isres/isres.c.
    * Changed encoding of src/nloptr.c from CP1252 to UTF-8.

09 November 2013, version 0.9.4:
    * Updated NLopt to version 2.4.
    * Changed tests to use unit testing package testthat (these are currently disabled).
    * Fixed a segfault that started to occur on the latest version of Ubuntu.
    * Slightly changed the build process (Removed -lstdc++ from linker statement. A file dummy.cpp (with C++ extension)
      is added to the source directory to ensure linking with C++. Thanks to Brian Ripley for bringing this up.)

31 July 2013, version 0.9.3:
    * Split lines longer than 100 characters in check.derivatives examples in two lines to comply with new package rules.
    * Moved vignettes from inst/doc to vignettes to comply with new package rules.
    * Removed dependency on apacite in vignette as an update of apacite on CRAN resulted in errors.

11 July 2013, version 0.9.2:
    * Made changes in bibtex file of documentation.
    * Removed CFLAGS, CXXFLAGS from Makevars.

version 0.9.0:
    * Introduced new print_level = 3. Shows values of controls (16 April 2012 on R-Forge).
    * Changed Makevars and Makevars.win to link to version 2.3 of NLopt compiled with --with-cxx option. This makes the StoGo algorithm available. (31 April 2013 on R-Forge).

18 November 2011, version 0.8.9:

    * Changed CRLF and CR line endings in src/Makevars to LF line endings to remove a warning from R CMD check.
    * Adopted some changes proposed by Brian Ripley to src/Makevars.win in order for nloptr to work with his new toolchain.

28 September 2011, version 0.8.8:

	* Updated src/Makevars to compile on Solaris.

24 September 2011, version 0.8.7:

	* Updated src/Makevars to compile on Solaris.

19 September 2011, version 0.8.6:

	* Updated src/Makevars to compile on Solaris.

03 September 2011, version 0.8.5:

	* Updated src/Makevars to compile a working binary for MacOS.

12 August 2011, version 0.8.4:

	* added new options:
		- data/nloptr.default.options.R: new file with a description of all options, mostly taken from the NLopt website (for internal use).
		- R/nloptr.print.options.R: function to show the description for a specific (set of) option(s).
		  E.g. nloptr.print.options( option="maxeval" )
		  nloptr.print.options() shows a description of all options if called without arguments.
		- added option to print a description of all options and their values ('print_options_doc' = TRUE/FALSE).
		- added option population to set the population of stochastic/global solvers ('population' = 1000).
		- added option ranseed which sets the random seed for stochastic solvers ('ranseed' = 3141). A value of 0 uses a random seed generated by system time.
		- option check_derivatives is no longer listed as a termination condition.
		- documented the option to set the tolerance of (in)equality constraints (tol_constraints_eq, tol_constraints_ineq).

	* tests/banana_global.R: new test file that uses the algorithms (CRS, ISRES, MLSL) and options ranseed and population.

	* src/nloptr.c: capture error codes from setting options.

	* R/nloptr.print.R: output gives 'optimal value of controls' when status = -4 (some error code), this is changed to 'current value of controls'.
