QueryParser Driver: Improve format filter

QueryParser Driver: Improve format filter

Allow multi-select in particular, and make negate more intuitive.

-format(at-d) would previously generate:
-item_type(a,t) -item_form(d)

Now it generates:
-(item_type(a,t) item_form(d))

Multi-select allows for things like:
format(at-d,g)

To generate:
((item_type(a,t) item_form(d)) || item_type(g))

Negating that results in:
-((item_type(a,t) item_form(d)) || item_type(g))

Signed-off-by: Thomas Berezansky <tsbere@mvlc.org>