git submodule remove?

[Tim Henigan <tim.henigan@gmail.com>]

Hello,

I recently encountered a situation where a user wanted to remove a submodule
from a repository.  Searching the mail archive, I found this thread
[1], but it does
not appear that it was ever followed up.

The Git Submodule Tutorial [2] has instructions for removing submodules, but it
seems natural to teach git how to "submodule rm".

This change would require git-submodule.sh to:
    1. Modify the .gitmodules file (remove the entry for the submodule).
    2. Modify the .git/config file (remove the entry for the submodule).
    3. Delete the newly untracked files.

Another option to consider would be a "submodule rm --cached" option which would
keep the newly untracked files.  However, with this option, I believe
it should still
descend into the submodule directory to remove the leftover submodule
".git" folder.

Is there another way of doing this?  If not, does this sound like a
reasonable change?

Thanks,
Tim Henigan

[1] http://article.gmane.org/gmane.comp.version-control.git/101610/match=submodule+remove
[2] http://git.or.cz/gitwiki/GitSubmoduleTutorial