Move src/* to root of package

Would you consider this change? I don't think it breaks anything, but lots of other tools all assume that setup.py and the module namespace starts at the root of the package directory.

This will make pygrooveshark conform to other tools' directory structure
expectations. For example, we can now install it with pip directly from
github.com:

    pip install git+https://github.com/koehlma/pygrooveshark.git\#egg\=grooveshark