Initially derived from jsonschema, by Ian Lewis and Yusuke Muraoka.

* James Turk
* Silas Sewell - Cosmetic fixes
* Filip Noetzel - lots of work towards being compatible with the draft-03 spec
* Kai Lautaportti - blank_by_default
* Filod Lin - fix for longs, validate as ints
* John Krauss - ignore additionalProperties with non-dicts
* Alexandre Conrad - IP address validator
* Michael Stephens - support for collections.Mapping
* Simon Weber - doc improvements
* Ahmed El-Hassany - fix for patternProperties on non-required fields
