Merge pull request #69 from opengm/master

update from master
Merge pull request #70 from opengm/master

update from opengm:master
add astar
add astar
change default ordering for Astar
 bugfix decomposition into kfans
Merge branch 'master' of https://github.com/joergkappes/opengm
Merge pull request #281 from joergkappes/master

Updates for DualDecomposition