evolve: refactoring of code related to pushing obs markers This removes duplicated code for the pushobsmarkers logic

merge with stable bunch of cleanup on stable

update readme

evolve: update cmddebugrecordpruneparents to the new markers creation API The parents information are now first class citizen. (caught by laurent using pylint)

evolve: drop useless return This return statement is never reached. This a actually a good new because its variable was undefined. We remove it. (caught by laurent using pylint)

evolve: add missing import (caught by pylint)

evolve: improve transaction related code to use the lock module Refactored some of the places where we are using locking in evolve to use the lock module and write less code. This should also fix a couple of bug where tr could be None at release time.

evolve: remove unused variables As suggested by pyflakes, remove 5 unused variables in the evolve module.

evolve: remove unused code in _evolveany remove some code that was doing nothing useful in _evolveany.

evove: remove unused imports Three imports where unused in the evolve module.

tests: ensure we keep capturing output In 3.4, output capture with bundle2 is disabled by default on local push.

inhibit: updating to a obsolete commit prints warning message We move the inhibition marker in the same wlock than the update operation, this clears the warning message. To make it work we display the warning message on lock release in evolve.

evolve: stop conditional wrapping of _checkinvalidmarkers We support down to Mercurial 3.3, all such version have this function.

evolve: stop conditional wrapping of _getbundleobsmarkerpart We support down to Mercurial 3.3, all such version have this function.