Big internal changes

The biggest change is using ImageFileCollection from ccdproc and eliminating that code from msumastro.

Internal rearrangement

0.8.0

v0.7.2

Adds limited python 3 support. None of the header processing code will work because it currently depends on astropysics, which will not be ported to python 3.

0.5.1

Includes building of table with all keywords, with a speedup from refactoring how the table is constructed.

Re-release

0.4.2

Bump version: 0.4.1 → 0.4.2