changed enum to const static in visitor return flags
Merge pull request #192 from joergkappes/RC-2.3

Refactoring of LF, LBP, TRBP, and multicut
Merge pull request #193 from joergkappes/RC-2.3

refactoring QPBO
merge done?
changed LOC to new visitor interface
Merge pull request #194 from DerThorsten/master

synched. my fork with RC-2.3 and changed LOC to new visitor interface
Merge pull request #51 from opengm/RC-2.3

update from opengm:RC-2.3