Merge pull request #19 from jhprinz/master

Added storage for order parameters
Merge pull request #21 from jhprinz/master

fixed merge in orderparameter.py
Merge pull request #22 from jhprinz/master

Added Davids Dihedral feature from #20
added shortcircut to ensemble calculations
support for forward and backward
fixed bug in loading orderparameters
Merge pull request #23 from jhprinz/shortcircuit

Shortcircuit
minor fixes and comments