description + source_state fields

• Add source state on transitions
• Fixed get_state_display with FSMIntegerField (#63)
• Fixed handling of transitions if target is None (#71)
• Added fsm_log_description decorator (#1, #67)
• Dropped support for Django 1.10 (#64)

Admin integration + pytest

• cleanup deprecated code.
• add codecov support.
• switch to pytest.
• add Admin integration to visualize past transitions.

Django 2.0 compatible

Merge pull request #51 from ticosax/release-1.4.0

Make 1.4.0 release

Version 1.0!

We're now fully Django FSM 2 and Django 1.7 compatible, so now's as good a time as any to bump to version 1.0!

Thanks to @scotta for his work on bringing us up to date with the latest Django FSM changes!