Fixed incorrect indexing in GetData with Rectangle.
Fixed TargetElapsedTime to exactly match XNA.
Made a bunch of tests public to make it visible to the unit test runner GUI.
Fixed incorrect default inactive sleep time.
Throw the correct exception when the time is negative.
Fixed exception message being set as parameter name.
Fixed missing argument exception in Game.Content assignment.
RunOneFrame() should not throw afterGame is disposed.
Made a few more tests public for GUI runner.
Updated the Linux Path
Merge pull request #2845 from vale981/patch-1

Updated the Linux Path
Merge pull request #2844 from SickheadGames/build

More Unit Testing Fixes
Added OpenTK.dll to MacOS project
Use common OpenGL codepath for all desktop platforms

This eliminates most `#if MONOMAC` regions in the OpenGL
implementation. The only major remaining uses are in Texture2D save
functions.
Use common OpenAL code path
Fixed obsolete warnings
Initialize OpenTK bindings through MonoMac
Switch MacOS to OpenTKGamePlatform
Dispose context on MacOS
Destroy the GameWindow before shutting down OpenTK