reconstruction to generate only the new commits since the last
	'--rejoin'.  '--ignore-joins' disables this behavior, forcing it to
	regenerate the entire history.  In a large project, this can take a long
	time.

--onto=<onto>::
	If your subtree was originally imported using something other than git
	subtree, its history may not match what git subtree is expecting.  In
	that case, you can specify the commit ID <onto> that corresponds to the
	first revision of the subproject's history that was imported into your
	project, and git subtree will attempt to build its history from there.
+
If you used 'git subtree add', you should never need this option.

--rejoin::
	After splitting, merge the newly created synthetic history back into
	your main project.  That way, future splits can search only the part of
	history that has been added since the most recent '--rejoin'.
+
If your split commits end up merged into the upstream subproject, and
then you want to get the latest upstream version, this will allow git's
merge algorithm to more intelligently avoid conflicts (since it knows
these synthetic commits are already part of the upstream repository).
+
Unfortunately, using this option results in 'git log' showing an extra
copy of every new commit that was created (the original, and the
synthetic one).
+
If you do all your merges with '--squash', make sure you also use
'--squash' when you 'split --rejoin'.


EXAMPLE 1. 'add' command
------------------------
Let's assume that you have a local repository that you would like
to add an external vendor library to. In this case we will add the
git-subtree repository as a subdirectory of your already existing
git-extensions repository in ~/git-extensions/:

	$ git subtree add --prefix=git-subtree --squash \
		git://github.com/apenwarr/git-subtree.git master

'master' needs to be a valid remote ref and can be a different branch
name

You can omit the '--squash' flag, but doing so will increase the number
of commits that are included in your local repository.

We now have a ~/git-extensions/git-subtree directory containing code
from the master branch of git://github.com/apenwarr/git-subtree.git
in our git-extensions repository.

EXAMPLE 2. Extract a subtree using 'commit', 'merge' and 'pull'
---------------------------------------------------------------
Let's use the repository for the git source code as an example.
First, get your own copy of the