Rework fo doMSSM.py

- doMSSM.py is now fit for the next iteration (tail fitting + bbb for remaining cases, with BB-Lite).
- migrated a few standards of doSM into doMSSM (e.g. and the main issue: doMSSM should not write into the package itself any more)
- added blinding part from doMSSM in doSM (but still needs a bit of testing to make sure that it really works).
- the rest is small changes and cleanups