Removing bug generated in the merge.
Minimal change to VariableOrIndividual.
Almost complete version of union of sets, needs some more testing.
Fix union as far as current test go.
Output in alphabetical order, useful for big lists of results. Currently the order was arbitrary.
Merge branch 'master' into union-sets
Remove comments.
Reversing order of grounding: constraints first, then rules. First step to remove certain easy constraints like functional with only one unbound predicate, e.g. votes(anna, demo) = 1 - 0.9 = 0.1
Improved grounding.
Remove printing results in tests.
Merge master into this branch.