Merge pull request #24 from opengm/RC-2.3

from rc2.3
Merge pull request #25 from opengm/RC-2.3

from rc2.3
Merge pull request #26 from opengm/master

from opengm master to my fork
added code to get fractional ad3 solutions
changed example a bit
changed example a bit
Merge pull request #257 from DerThorsten/master

added code to get fractional ad3 solutions