Use qtfaststart for relocating MOOV atoms

This pull request resolves issue #10 by including qtfaststart to relocate MOOV atoms. I added an additional setting in case users don't want to move it. 

Qtfaststart is pulled in via a submodule, so please let me know if that works for you. It seems the downside of submodules is that you probably can't edit them. But I suppose you could always create your own fork and pull that in as a submodule. You can keep your fork up to date with upstream by adding the source repository as an additional remote. Read more about it here - https://help.github.com/articles/fork-a-repo but for now I can't see a reason we'd need to fork qtfaststart.