Robust.UnitTesting was both ALL tests for RT, and also API surface for content tests.
Tests are now split into separate projects as appropriate, and the API side has also been split off.
* Removed the Interfaces folder.
* All objects inside the GameObjects subfolders are now in the GameObjects namespace.
* Added a Resharper DotSettings file to mark the GameObjects subfolders as not providing namespaces.
* Simplified Robust.client.Graphics namespace.
* Automated remove redundant using statements.
