Added some deforming mesh stuff
Fixed the nonlinear heat transfer model (again)

* Moving mesh code now works. Just need to update the equations
        to include mesh velocity now.
* This version of the heat transfer model might still be incorrect.
        It appears to work, and adding in the term for gradient of
        thermal conductivity adds only a small contribution to the
        final answer, as expected. However, it has not yet been
        validated.