	Send a patch from the current or specified topic branch as
	email(s).

	Takes the patch given on the command line and emails it out.
	Destination addresses such as To, Cc and Bcc are taken from the
	patch header.

	Since it actually boils down to `git send-email`, please refer
	to the documentation for that for details on how to setup email
	for git.  You can pass arbitrary options to this command through
	the '-s' parameter, but you must double-quote everything.  The
	'-r' parameter with a msgid can be used to generate in-reply-to
	and reference headers to an earlier mail.

	WARNING: be careful when using this command.  It easily sends
	out several mails.  You might want to run

		git config sendemail.confirm always

	to let `git send-email` ask for confirmation before sending any
	mail.

	Options:
	  -i		base patch generation on index instead of branch
	  -w		base patch generation on working tree instead of branch

	TODO: 'tg mail patchfile' to mail an already exported patch
	TODO: mailing patch series
	TODO: specifying additional options and addresses on command
	      line

