added helper module
added missing repository
moved ColumnCombinationBitset to helpers
implemented minus on ColumnCombinationBitset
added needed methods for fun (implementation pending)
added containRealSubset method
implemented unreal subset test
Fixed interface of recursive getNSubsetColumnCombinationsSupersetOf
method
implemented size on ColumnCombinationBitset
broken commit for pull, trying to fix find()
Merge branch 'master' of ma2013@code.hpi.uni-potsdam.de:ma2013.git into ducc_dev
added methods addColumn and getSetBits
added bottom up implementation of getNSubsetColumnCombinationsSupersetOf
added test for subsets greater than the subset (return empty list)
implemented intelligent super set sub set generation
added stubs for the direct sub and super sets
implemented direct super sets
implemented removeColumn and getDirectSubsets
implemented getContainedOneColumnCombinations
implemented union
removed unnecessary method or (same as union)