Moving biometrics-related functionality to bob.bio.base

As Bob keeps its trajectory to serve more types of systems, it becomes less and less obvious to keep biometrics-related functionality inside this package. I'm proposing we move those into bob.bio.base, which is the place they should have been in the first place.

A few things that come to mind:

• All score loading/saving functionality
• OpenBR exchange support
• The scripts, which are tunned for Biometrics-style reporting (and can only load biometric score files)
• Not sure about all the identification stuff, maybe generic enough to keep here?

Thanks for your feedback.