Custom Data sample implementation
added CustomData class tests
added getCustomMethod to fit into app style

added tests
added CustomData documentation
updated remove custom data field method to behave like in Java
added async module (was initially added in CollectionResource.each branch)
add CustomData save method, which supports field removal
updated CustomData docs
updated CustomData docs
updated CustomData, _removedFields are hidden field now
fix #22 - added sample usage of CustomData - can fail if Stormpath(default app) doesn't have default account store

will be updated after implementation of SocialLogin and Account Store Mappings
add doc for CustomaData.get method
Merge pull request #16 from valorkin/custom_data

Custom Data
Merge branch 'master' into account_store_mapping

Conflicts:  example.js
updated AccountStoreClassFactory
added  Provider resource
added  ProviderData resource
added Directory.getProvider
added Account.getProviderData and isNew flag
added Application.getAccount