First generate certainly, then possibly table

[Broes De Cat]

Given the formula ?x: P(x) and structure P<ct> = {10000}

Then it would be beneficial if the grounder would first generate the certainly-true table for the exists and detect it can stop early. We might do this by making uniongenerators in the case that certainly-true is non-empty and small (if large, the union generator overhead will be large).

[Bart Bogaerts]

First: fix issue #232

[Broes De Cat]

Or create a new generator which checks whether the ct is non-empty and if so, first generates one element from it?

[Bart Bogaerts]

Branch bettergenerators contains a first attempt. However, it is not yet working completely...