match: fold match into _match base class

match: add exact flag to match() to unify all match forms

match: redefine always and never in terms of match and exact

match: fold _globprefix into _roots

match: optimize escaping in _globre - localize re.escape - fastpath escaping of non-special characters

match: remove head and tail args from _globre

match: fold _matcher into match.__init__

match: rename _matchfn to _buildmatch

match: optimize _patsplit

match: tweak some names

match: simplify _matcher - get rid of special case - simplify anypats logic - fold inckinds and exckinds

match: split up _normalizepats

match: optimize _globprefix

match: unnest functions in _matcher

match: kill unused defaults on _globre

match: kill test in matchfn

match: refactor matchfn generation

match: move util match functions over

util: privatize globre

match: refactor patkind add patkind(pat) to match change external users change util.patkind to _patsplit

match: add some default args

match: change all users of util.matcher to match.match

tests: add tests for new pre-push logic (issue736) Co-contributor: Henrik Stuart <henrik.stuart@edlund.dk>

named branches: improve pre-push logic (issue736) Each named branch is considered separately, and the push is allowed if no new branch heads are created for any named branch to be pushed. Due to some tests's use of --debug, their output will change after this addition. This has been fixed as well. Co-contributor: Henrik Stuart <henrik.stuart@edlund.dk>