debugbuilddag: use memctx for speed This drops the options to run arbitrary shell commands within commits and the option to create a file that gets appended to in every revision. It now supports to not write file data at all, which is very fast for generating a pure 00changelog.i (useful for discovery tests, for instance). Timings for 1000 linear nodes: * Old `hg debugbuilddag -o '+1000'` took 4.5 secs. * New `hg debugbuilddag -o '+1000'` takes 2 secs. * New `hg debugbuilddag '+1000'` takes 0.8 secs. (The last one creates only 00changelog.i).

localrepo: reuse parent manifest in commitctx if no files have changed This speeds up the in-memory version of debugbuilddag that I'm working on considerably for the case where we want to build just a 00changelog.i (for discovery tests, for instance). There are a couple of test changes because node ids in tests have changed. The changes to the patch names in test-mq-qdelete.t were required because they could collide with nodeid abbreviations and newly actually do (patch "c" collides with id "cafe..." for patch "b").

bundlerepo: fix and improve getremotechanges Fixes the regression where incoming could show local changes introduced by rev 72c84f24b420.

hgrc.5: mention new 'case collision' handling for ui.portablefilenames

win32: remove obsolete bookmarks and parentrevspec extensions from mercurial.ini

bundlerepo: drop struct

bisect: fix indent level