Use git submodules for dependency tracking.

Instead having binaries inside the git repositories we might want to use git submodules and automatize their build. This makes it easier to create proper packages for distributions. Currently it creates a DLL hell because openra bundles many libraries and this confuses automatic dependency generation on http://build.opensuse.org/ The github web-interface also automagically links to the dependencies so it becomes clearer for developers and end-users what code is used.

*ICSharpCode.SharpZipLib:* `nant build-net-2.0` works
*Mono.Nat:* plain and simple `xbuild` works best
*Tao:* This is somehow complex. I don't know how this works. All the .sh scripts will fail and it needs to create the files for autotools and nant with some other tool. Help is appreciated.