implemented pmssm10

Implemented pmssm10

This pull request gives a good idea of which files have to be changed to implement a new model.

back end:
*ObsCalculator/interfaces/softsusy.py
*ObsCalculator/inputs.py (convenience wrapper)
*Storage/old_mc_rootstorage.py (this is soon to be replaced)

front end:
*mc_multinest.py
*mc_point.py