Improve operators together with (not) element of

[favu100]

This could be treated similar to constructs like x : NATURAL (which does not generate the infinite set NATURAL, but checks whether x >= 0 instead).

One of such operator is interval. E.g. x : 0..5 should not generate the set with all elements in 0..5, but rather checks whether x >= 0 & x <= 5

Other operators could be improved as well (see kernel_mappings.pl in ProB Prolog: binary_in_boolean_type/2, binary_not_in_boolean_type/2, unary_in_boolean_type/2, unary_not_in_boolean_type/2)

[favu100]

This issue is solved now