Repo maintenance: Full history revision

All unnecessary objects bloating the repository have been removed.
The history hasn't functionally changed (meaning all tagged versions
and commits still work perfectly when checked out), but all tags
and commit hashes are different have. The functional changes are
to these directories only:

 * Unity Free Flight/Assets/Standard Assets
 * Unity Free Flight/Library

You will now need to manually import all used standard assets,
currently there are as follows:

 * Character Controllers
	* scripts only
 * Skyboxes
	* Sunny1Skybox
	* Textures
 * Terrain Assets
	* (All)
 * Tree Creator
	* Sources
		* Materials
	* Trees
		* (all)
* Water (Basic)
	* Daylight Simple Water
	* Sources
		* Materials
		* Objects
		* Scripts
		* Shaders

Official documentation on these changes will be released soon.