context: add a method to efficiently filter by match if possible For non-working contexts, walk and matches do the same thing. For working contexts, walk stats all the files and looks for unknown files, while matches just filters the dirstate by match.

dirstate: add a method to efficiently filter by match Current callers that require just this data call workingctx.walk, which calls dirstate.walk, which stats all the files. Even worse, workingctx.walk looks for unknown files, significantly slowing things down, even though callers might not be interested in them at all.

purge: prefer util.unlink instead over own removefile

keyword: bump copyright year

keyword: really clean up kwdemo temp tree

graft: make --force apply across continues (issue3220) Since --force determines the list of revisions to be grafted, it doesn't really make sense for users to have to keep typing --force --continue as they continue grafting.