Merge pull request #324 from joergkappes/master

Add FoE
Merge pull request #325 from joergkappes/master

LP/ILP update (CPlex and Gurobi)
Merge pull request #327 from joergkappes/master

Bugfixes/Warningfixes by Alex Fix
Implement LPGurobi::add_constraint() and add a dirty flag for model updates.
Merge pull request #329 from chaubold/fix/gurobi_constraints

Implement LPGurobi::add_constraint() and add a dirty flag for model updates.
Merge pull request #82 from opengm/master

update from master