Update MathHelper tests.
Update Color class and tests.

Added constructor to Color to create a color from a Vector3.
Added constructor to Color to create a color from a Vector4.
Color class should now have 100% test coverage.
Updated Point class.

Point now has a field for the Z component of its coordinate.
Added tests for the Point class.
Updates to vectors.

Added Vector4 Extensions.
Added ToFloatArray(Vector3) to Vector3 Extensions.
Added tests for vector extensions.
Updates to Extensions and MathHelper tests.

Added tests for all number extension classes.
Renamed some tests in MathHelperTests.