Third beta release for 0.1

Future-proof for Astropy v2.

Second beta release

Documentation completed. Initial commissioning report now available. Minor API improvements based on lessons learned while writing the documentation. Incomplete OBSMODE now displays possible valid values. Now able to read WFPC2 ramp filter OBSMODE.

First beta release

First beta release that successfully passed initial commissioning test (#23). This goes with synphot 0.1b1 as well.

Note: Documentation still not done.