Revert "Pin Astropy at 0.3.1 release."
Revert "Pin Astropy at 0.3.1 release."

Astropy 0.4+ is OK, but requires Aplpy>=0.9.12 !

This reverts commit 95c2d84a975ac35dcaa20070c5094e2279e6a6b5.

bartscheers/banana,bartscheers/banana,bartscheers/banana