Fix for proper Vim/Vundle support

Vim and Vundle expect color schemes to exist inside a `colors` directory rather than a root `vim` directory, so I've moved all .vim files and updated the README accordingly.

I also updated the build.xml, but I didn't see any instructions for how to run a build to test my change. Please let me know if I've somehow broken some the build process and I'll make any necessary changes.

Hope this helps!