Refactored util/transforms.py translate, scale and rotate to just return

Refactored translate, scale and return to just return a matrix to be multiplied instead of the matrix multiplication being done in the method

Adapted scenen linear transforms as appropriate

Adapted examples as appropriate (except for ipython notebooks, cannot test those)
There is some risk of over-engineering this -- +1 for one `rotate` function consistent with OpenGL conventions (I guess that's degrees) and clear docstring saying that's the behavior and why