Fix precedence of "not" to be above "and/or" but below comparisons.

This fixes ticket 384 by @Draugrs, where expressions like:

   not IcyVeinsCooldownRemains() > 0

was being parsed as:

   (not IcyVeinsCooldownRemains()) > 0

instead of:

   not (IcyVeinsCooldownRemains() > 0)