Integrate span in your GIT workflow using submodule

You can easily use span as a git submodule for your project.
So you will have in your working copy the content of span at a certain state, because the link is only a reference to a commit.

It can be done with Source Tree multi-platform Git Client. Here is a step-by-step :
http://blog.sourcetreeapp.com/2012/02/01/using-submodules-and-subrepositories/