AbstractProviderAccountRequest and ProviderAccountRequest's builder moved to impl pkg
ProviderAccountResult is not a Resource any longer -> ProviderAccountResultHelper constructs it
Created CreateDirectoryRequest and removed dir.setProvider(provider)
Merge branch 'social_login_support' of https://github.com/stormpath/stormpath-sdk-java into social_login_support

Conflicts:
	api/src/main/java/com/stormpath/sdk/provider/CreateProviderRequestBuilder.java
	api/src/main/java/com/stormpath/sdk/provider/ProviderRequestFactory.java
	api/src/test/groovy/com/stormpath/sdk/provider/FacebookAccountRequestBuilderTest.groovy
	api/src/test/groovy/com/stormpath/sdk/provider/GoogleAccountRequestBuilderTest.groovy
	impl/src/main/java/com/stormpath/sdk/impl/provider/DefaultFacebookRequestFactory.java
	impl/src/main/java/com/stormpath/sdk/impl/provider/DefaultGoogleRequestFactory.java
	impl/src/test/groovy/com/stormpath/sdk/impl/provider/AbstractProviderAccountRequestTest.groovy
	impl/src/test/groovy/com/stormpath/sdk/impl/provider/ProviderAccountResolverTest.groovy
	impl/src/test/groovy/com/stormpath/sdk/provider/ProvidersTest.groovy
Removed unnecessary tests