title: Easiest way to convert between Matrix and Quaternion and EulerRotation in PyMEL
body: <p>I know how to perform the math to convert between a 4x4 matrix, quaternion, and euler angles given a rotation in any other form.  I was just hoping in PyMEL that there would be built-in ways to convert.  None have really worked for me so far.  Anyone out there know the best way, or a commonly-used library for this?</p>
  
  <p>Thanks!</p>