This commit adds the MatchLimit function, which it the
same as Match but will limit the complexity of the input pattern.
This is to avoid long running matches, specifically to avoid ReDos
attacks from arbritary inputs.

How it works:
The underlying match routine is recursive and may call itself when it
encounters a sandwiched wildcard pattern, such as: `user:*:name`.
Everytime it calls itself a counter is incremented.
The operation is stopped when counter > maxcomp*len(str).