Port SunPy to Astropy helpers

This is the first shot at using all the astropy magic for sunpy.

Commands now available:

Run `--help` for more info on each.
```
python setup.py test

python setup.py build_sphinx
```

This also uses astropy version numbering for dev and git hashes, and means you can build the ANA extensions without numpy installed (numpy is compiled into a local path for compiling sunpy).

And no doubt many other things I have forgotten.