parser error handling
distinctor with min occurrences
adding LeftEntityExtractorTest
Xor fix and test
better heuristic
small fixes
BestSelector fix and test
Merge branch 'master' of https://github.com/matfed/CoAnSys
allow to specify separate citations source
Merge pull request #217 from matfed/master

Better heuristic implementation and bugfix in BestSelector