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 33289: Version 0.9.0.0
- Updated the TwitterAccessor to have null checking in the TryExecuteQuery so that it returns null
- Implemented missing methods to the TweetController
- Moved the geo query parameter generation from the TweetQueryGenerator into the GeoQueryGenerator
- Extracted the query generation for Tweet requests into the TweetQueryGenerator