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)
I don't mind having matrices. They are frequently used in this kind of use case, where you have 2D transformation matrices you want to multiply.