Valhalla

* Renamed Schema.name to Schema.schema_name to eliminate the collision caused due to the frequent and obvious need for a field called "name".

* strings._pre_hook now converts NoneType to empty string if received.

* Added the strings.key_lookup filter. This is used for creating lookup dictionaries to convert input values to logical equivalents. For example, schema.state_name.key_lookup({'MA': 'Massachusetts'}) would convert an incoming value of "MA" to "Massachusetts". You can set missing key behavior via nomatch param.

* Added support for dict-based schema definitions via Schema.from_dict(dict_scheme, **kwargs)
* Fixed collections.drop_keys and collections.contains to support *args for convenience.

* BUGFIX: validating required fields now properly recognizes fields supplied with alternate names

* Added the casting.decimal filter and tests.
* Added Schema.results not sure why this was not added earlier. Brain fail.
* Added full unicode support via Schema(force_unicode=True) . Leaving this set to True will
cause the schema and the data input to be intelligently casted to unicode where appropriate.