Merge pull request #272 from joergkappes/master

use functors for message passing operations
Merge pull request #273 from joergkappes/master

Updates for DualDecomposition
python docs: Added CMake cache var toggle building of sphinx documentation.
Merge pull request #274 from stuarteberg/master

python docs: Added CMake cache var toggle building of sphinx docs
Merge pull request #276 from joergkappes/master

remove obsolet include
Merge pull request #69 from opengm/master

update from master