Split formal language support up into syntax, semantics, and interpretations in-between.

* [FORMAL_LANGUAGE,SC] Exporting logical connectives.
* [FORMAL_LANGUAGE,SC] Made lots of changes in order to decouple syntax from semantics, from interpretation in-between.
* [INTERPRETATION,NEW] New module, taking the interpretation code from FORMAL_LANGUAGE.
* [INTERPRETATION,NEW] Added add_interpretation/2 for individual constants and predicates.
* [UNIVERSE_OF_DISCOURSE,NEW] New module, taking the semantics code from FORMAL_LANGUAGE.
* [UNIVERSE_OF_DISCOURSE,NEW] Added add_object/1, add_relation/2, object/1, relation/2, universe_of_discourse/1.
* [UNIVERSE_OF_DISCOURSE,NEW] Use UUIDs for objects and relations.