0.4.12 and some housekeeping

Version bump and contributors.

Merge pull request themartorana#48 from nicholasserra/nicholasserra-b…

…atch-error

Inactive Recipient error and tests

Bump to 0.4.5, add mflaxman as contributor

Update core.py

0.4.3, add Dave Peticolas as contributor

Add back in license file, more PyPi compatible

Missing 0.4.1 updates

Update copyright date and versions