addremove: add support for the -S flag Git and svn subrepos are currently not supported. It doesn't look like git or svn have these commands natively, so that's an area for a git or svn expert.

commit: propagate --addremove to subrepos if -S is specified (issue3759) The recursive addremove operation occurs completely before the first subrepo is committed. Only hg subrepos support the addremove operation at the moment- svn and git subrepos will warn and abort the commit.

subrepo: store the ui object in the base class This will be used in the next patch to print a warning from the base class. It seems better than having to explicitly pass it to a new method, since a lot of existing methods also require it.

commit: abort if --addremove is specified, but fails This will be required when subrepo support is added, in order to ensure consistent commits when a subrepo flavor doesn't support addremove.