Make the glfw source to a submodule?

[joe9]

Hello,

Just want to check if you could make the glfw/ source a submodule, so, it gets easier to track with the origin.

Thanks

[Mokosha]

I think this is a good idea. There are some files that have been removed that we keep around when we upgrade to the latest GLFW, so we're not quite tracking the release. Also, in the current directory structure it's a bit difficult to tell what we've introduced (like glfw_config.h) versus what's in the release. Ostensibly, listing the necessary files in cabal should have them be bundled up when distributing to hackage anyway.