Update for MadDM v.2.0 released

Written for MadDM by Mihailo Backovic on 2015-06-29

An update for MadDM v.2.0 is available. The update contains a fix for a small bug which caused the code to crash in some cases if only relic density module was run.
In addition we also fixed a bug related to models which allow for flavor changing dm interactions in direct detection.
Please update to the last version to ensure the best MadDM experience!