[commit-patch] Add --retry option to commit-partial for when the edited patch fails apply the first time.

This avoids tyring to do diff-hunk-next in autodetect-patch-directory-root
and is more flexible all around.

There are now just 2 functions:

commit-patch-buffer - Fully automatic, takes no arguments (bound to C-c C-c).
commit-patch-buffer-manually - Takes 2 interactive arguments.

Dropped commit-patch-current-buffer which took just a directory argument as
it seems pointless now--use commit-patch-buffer-manually instead.

This takes commit-patch down to zero arguments!

[commit-patch-buffer.el] Add commit-patch-current-buffer which skips the "ask for buffer to patch" step.

So far in all my years of commit-patch usage I don't think I've ever needed
to commit a buffer that I wasn't looking at right then.

END always gets run, even when we exit via signals and we have a handler.

Bzr doesn't seem to have amend support. :-(

[commit-patch] commit-partial is allowed to have zero or more file name arguments on the command line.

I got errors when running commit-patch.  It looks like log-edit's
arguments changed meanings somewhere along the line (there's a comment
in the source).  I'm using GNU Emacs 23.1.50.1 (x86_64-pc-linux-gnu,
GTK+ Version 2.16.1) of 2009-07-31 on platinum, modified by Debian.
Here's a patch to fix it in my Emacs, but I didn't test with Emacs 22.

[commit-patch-buffer.el] no need to load diff-mode, just name sure our hook gets added if it ever does load