Move setup.py to root but keep src

This is a bit more invasive. Here's the summary:

1. Move setup.py out of src
2. Move all metadata vars from grooveshark/__init__.py to grooveshark/version.py (allows us to just execfile that instead of importing the entire package in setup.py)
3. Export all metadata vars from version.py and import them in grooveshark, effectively keeping the nice grooveshark.__version__ etc. namespace.
4. Tell setup.py where the package directory (src) is