added pattern tableau for conditional unique column combinations

added pattern tableaus as display type for conditional uniques

Small fix in ColumnCombinationBitset where a ImmutableList was expected but the current Implementation is a List. Missing change after refactoring in the main repository.

Add a clone() method for PositionListIndex, which is a deep copy.
This Test is an artifact of a previous class construct and was out commented when the code changed heavily. I finally deleted that out commented code. I personally don't think that an equals/hashcode test is necessary for this class. But I can write on if you wish it.