IP module consolidation

Created by: laurentes

As discussed on the mailing list previously, there is a need to consolidate some parts of the code. In particular, the Image Processing module (IP) is one of the largest one and contains many algorithm ports from late torch5spro and others.

I've started this consolidation procedure. However, this is quite a large work. This ticket aims at tracking the consolidation procedure of this IP module, with remarks and TODOs. Feel free to add your feature request.