Fix the positive trace branch in QuatFromRotationMatrix

Having made some number changes I didn't ensure that the operations
still made sense and was multiplying values I should have been dividing.
LookAt now works from any position to create any look-at orientation.
Use existing LookAt calculations instead of new code

The LookAt matrix factory method is known to work properly and as
QuatFromAxes creates a matrix anyway lets just use the methods that are
definitely working.