Worked on tests and some minor additions

Mostly new tests for existing code, made some minor additions and improvements.

 * Color class can now be created from Vector3/4
 * Point now has a Z member
 * Vector4 now has extensions similar to Vector3, also added a new extension method to convert a single vector to float array (not just an array of vectors to an array of floats)
 * Added tests for some code that didn't already have any
 * Some renames to existing test methods