Use submodules

[1ace]

You should use git's submodule instead of copying all the files from your dependencies into your own repo.
It also makes it easier to see what code you're providing, and allows everyone to update things individually :)

[alexandernst]

I had a lot of headache with git submodules, so I ended up doing it the easy way. I know it's not the right way, but I just didn't want to deal with it. I'll accept PRs if you're interested :)