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)
Re: degrees vs radians, perhaps a better question is how this is more commonly used--to rotate some nice fraction of a circle (in which case degrees makes more sense; `rotate(90)` is simpler than `rotate(np.pi / 2)`), or in trigonometric relationships (in which case radians are simpler; `rotate(np.arctan2(y, x))`). 

It's a minor issue here, though..