Commented Feature: Update : [code/unity] Migrate application design to use Unity for IoC [1691]

Implement Unity and Dependency injection to enable the development of Unit Tests as Tweetinvi currently only have Integration tests.
Comments: Associated with changeset 33495: Version 0.9.0.0
- Updated code logic for CreateFriendship(IUserDTO) - No validty check is performed anymore by the query executor
- Added test for CreateFriendship(IUserDTO)