Color: fixed some issues and implemented some missing methods
TestCenter: refactoring (moved all ConvertEquals-Methods to the new AssertHelper)
DataFactory: extended by normalized random floats
TestCenter: all Color tests are green now
SpriteBatch/SpriteFonts: rendering of SpriteFonts is finished now
Added test cases for Vector2 static Transform
Added test cases for Matrix: CreateRotationX, CreateRotationY, CreateRotationZ, Multiply and CreateTranslation
Matrix: Fixed a bug in CreateRotationY (wrong result)