Extracted out Swagger ApiDeclarationFile into it's own class
Reworked #generate_doc so it doesn't require a call to camelize_keys_deep
Switched to a non-modifying version of #camelize_keys_deep
Make camelizing of model properties configurable.

* Fix model tag name so it is the same case as the symbol passed in. A
swagger_model :Tag was being put into the json models hash as 'tag'
instead of 'Tag'
* Created ApiDeclarationFileMetadata class to make it clear the fields
that are needed on the ApiDeclarationFile metadata object
* Updated readme
Merge pull request #55 from aaronrenner/make_camelize_model_properties_configurable

Made camelize model properties configurable and fixed swagger_model name capitalization issue