revset: fix %r handling in formatspec

rebase: use revset as soon as possible in internal logic The buildstate function now take a set of revs. Logic related to --source and --base option have been moved in the main rebase function. In the process this fixes a bug where the wrong source changeset might be pick. This explain the changes in hgext/rebase.py

revset: add %r for embedded revset support to formatspec This allows folding external revsets or lists of revsets into a revset expression. Revsets are pre-parsed for validity so that syntax errors don't escape.

revert: warn that subrepos cannot be reverted (tests added by mpm)

merge: expand environment variables and ~/ in tool.executable hgrc(5) already implies that this works, so we might as well support it. Another approach would be to implement this in util.findexe(): that would benefit other callers of findexe(), e.g. convert and anyone calling the user's editor. But findexe() is really implemented in both posix.py and windows.py, so this would make both of those modules depend on util.py: not good. So keep it narrow and only for merge tools.

minirst: improve test harness

minirst: add style flag to format

minirst: add basic HTML formatting support

graft: use status verbosity for reporting grafts

contrib: add a script to help diagnose raw output of the cmdserver