MatchVector, AnnotationMatch, TokenMatch are now MatchData
MatchData is value_type of Match which now has get_value/set_value
Match has also copy construction working properly now
Default value for Match holds MatchVector so adding $m:_M var in grammar works as intended.

The prefix like "$m:" signifies type in WCCL, but in Variables code it comes from template argument; in this particular example, the <Match> type.

The design doc for llook/rlook was incorrect, swapping the semantics per the updated docs and swapping argument order for llook.

Added parentheses for all "general" operator rules (string_operator, bool_operator, symset_operator and position_operator).

'unify the names of the rules').