Weird unsatcore output for false-defineds

[Bart Bogaerts]

Typical error made by students attached..

Unsatcore output is not understandable: should refer to the definition defining P false...

[Broes De Cat]

Not sure what you expect here, the result is a perfectly sensible minimal unsat core? (although the text should be a bit more informative for students) Only bug is the printed line number, which will have been lost during some transformation, will check this.

[Broes De Cat]

Refs #535: rules are now (first time ever) parsed with proper location info.

→ <<cset 49ce66d7636b>>

[Broes De Cat]

It now refers to a variable that was created internally. Should rather refer to the fact that it added a rule to represent that any atom over the defined symbol is false if it cannot be derived to be true.

[Broes De Cat]

Fixes #535.

→ <<cset a78f7d0f9c08>>