Fix coverage checking for functions matching constants

Generates an example case for a constant which isn't matched explicitly.
This should be sufficient to ensure that any case which isn't given
explicitly is also handled.
Refactoring of parser to Trifecta, documenting and updating some
items/fixing some issues.

Test 002 commented because of temporary disabling of TT quotation
support.

Regression Test 003 and Test 020 have updated expected values (which
fixes previously erranous line number report from old parser).