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 33273: Version 0.9.0.0
- Implemented SavedSearchJsonController
- Extracting SavedSearch query generation into SavedSearchQueryGenerator
- Implemented Help to provide static access to the HelpController methods
- Added methods from MessageController into the Message static accessor class