Support the required format of the latest schema version
Cheshire 5.3.1
Adds support for `patternProperties`.

http://tools.ietf.org/html/draft-zyp-json-schema-03#section-5.3
Adds a little bit more cleanup.
Version 0.5
New feature: custom field validators.

Passing in :extra-validators to the validate function will OR the
results of the original function with the one in the map.

This allows nearly endless customisation to the behaviour of the
validation.
Version bumped
Than not then.