Re-worded some odd-sounding English.
Added XML documentation for Rectangle.ToString() and the Vector2 constant vectors.
Added XML docs for Vector2.Add()/Subtract().
Cleaned up a few issues in a recent documentation patch.
Merge pull request #2865 from dneelyep/patch-3

Minor documentation additions
Merge pull request #2869 from SickheadGames/develop

Fixed 2MGFX Bug
Add XML documentation for Vector3/4's static vector properties, and their add/subtract methods.
Added XML docs for Vector2/3.Negate(). Holding off on Vector4 since I'm not sure if Vector4s are used in the same way (a direction) as Vector2/3s.
Merge pull request #2870 from dneelyep/patch-3

Add XML docs for Vector3/4.Add/Subtract/static vectors, and for Vector2/3.Negate
Restored old behavior of the sprite effect only being applied once at sprite batch setup.
Timer should only be initialized once when using RunOneFrame()
Applied same fix for custom effects as in the common SpriteBatcher.
Merge pull request #2874 from GhostTap/RunOneFrameTimerFix

Timer should only be initialized once when using RunOneFrame()
Merge pull request #2873 from SickheadGames/customfx

SpriteBatch Effect Fix