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You can roll your own using latex-diff. It comes eg. with TexLive and has some (limited) built-in support for different versioning systems.

We are rolling out support for Latex & Git with our new latex editor in the next two weeks. Sneak peek here: http://cl.ly/image/3u3Z3f40382K

Drop me a line toni@banyan.co if you want early access.