fix match token-level condition: immediately terminate and return empty match result when curr pos is outside sent

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.

MatchResult - change constructor so when you provide Match it defaults to matched = true.
TokenCondition - be a bit defensive about possibility of inner predicates changing $_