chgserver: add utilities to calculate mtimehash mtimehash is designed to detect file changes. These files include: - single file extensions (__init__.py for complex extensions) - mercurial/__version__.py - python (sys.executable) mtimehash only uses stat to check files so it's fast but not 100% accurate. However it should be good enough for our use case. For chgserver, once mtimehash changes, the server is considered outdated immediately and should no longer provide service.

tests: rename 'test-module-import.t' into 'test-check-module-import.t' This test is checking our source code to ensure style and correct behavior (eg: no cycle). Current convention is that such tests starts with 'test-check-' so we flock this on back with the others.

pull: deactivate a bookmark not matching with the destination of the update Before this patch, "hg pull -u" with a target doesn't deactivate a current active bookmark, which doesn't match with the explicit destination of the update, even though bare "hg update" does so. A "target" can be provided through: - option --rev ANOTHER - option --branch ANOTHER - source URL#ANOTHER