multiple files works but does not work for hash-type yaml files
Hash-type yaml files can have multiple files loaded for a single model

- Yaml file of array type and of hash type cannot both be loaded for a single model (ActiveHash::FileTypeMismatchError is raised)
- fix typo in provences.yml
- remove duplicate constant removal in active yaml spec
Add to readme
Remove bad comment
ActiveJSON is a simple ActiveFile subclass
Active JSON works for multiple files

- include tests for hash-style json files as well
- ActiveFile::HashAndArrayFiles module for shared behavior
Update read me to include documentation for ActiveJSON
Merge pull request #83 from rheaton/feature/active-json-multiple-files

ActiveJSON with multiple files support