It would create one only if top-level parse_match_operator
parser rule had been used. Now it creates it within
match_rule_operator parser rule, so it works for parse_wccl_file
as well.

Allows for application of all rules on an annotated sequence
via apply_all method.

This reflects the fact that positions stored in matches are
absolute positions, while Position type is used in the
language as position relative to current position in the
sentence context. So mixing the two was confusing at the very least.
This also actually fits the most recent version of spec,
which no longer mentions Position, either.

It didn't like passing reference to something that could be treated as a value.

Variables is noncopyable but default copy constructor was apparently working in VS.

Each subsequent rule was reusing variables object, which wasn't good.
Parsing of sequences had to be changed not to end with semi,
and it wasn't actually passing on lexicons in the first place.

longest() and oneof() operator takes boost::shared_ptr<std::vector<boost::shared_ptr<ConjConditions> > >

So it's clear it's not about MatchRule at all.

Sort of a comeback of an old idea. It's either this,
or adding a third parameter soon for lexicons.
I went with this as this makes it easier to add yet
another thing to toss around, if such need ever arises.