2nd PR for MultiMutDes-EF

[shaoqx]

ModelingEngine

• Added a based ABC for modeling engine in general
• Added thermostability engine
• Half-done for RosettaCartesianddGEngine

Mutation

• changed the import structure for Mutation class. It is needed by _interface.

Analysis

• Added stability calculations
• Added a method for the coarse dEF calculation

Workflow App

• added main script for MultiMutDes

[chrisjurich]

Good job! Again, I appreciate the rebasing so that I can include the features in my own branch :)