cleaned up unit tests

removed a lot of duplication, put the most important assertions closest
to the test, moved assertions that objects have not changed values
during an operation to the bottom of tests, simplified some tests, added
a small amount of Quaternion tests
Quaternion operator overload tests all pass
Quaternion tests complete, two failures

Finished first pass of all quaternion tests, removed all mzin::
references in favor of single using statement in TestMath.h, Slerp and
RotationOrientationInverse seem to have bugs