hg.py: add islocal() and defaultdest() functions, refactor
islocal tells if a repo or url is local.
defaultdest returns default path for clone if explicit path not given.
clone can now take repo or url as source
(the addremove command is deprecated; use add and remove --after instead)
adding dir/bar
adding foo
dir/bar
foo
(the addremove command is deprecated; use add and remove --after instead)
adding dir/bar_2
adding foo_2
dir/bar_2
foo_2