Towards pure python phase1

Hi guys,

This MR is another step towards getting rid of our C++ code and have as much as possible pure python code. In this first step, I'll get rid of code that we are not using for several years.

A second MR will come in the near future with more cuts in the code and the ported versions of essential stuff.

Follow the features that will go away in this MR.

• bob.ip.base.SIFT
• bob.ip.base.VLSIFT
• bob.ip.base.VLDSIFT
• bob.ip.base.Weiner
• bob.ip.base.MultiscaleRetinex
• bob.ip.base.SelfQuotientImage
• bob.ip.base.GSSKeypoint

Please, let me know if any objection