Version number -> 0.6.0

Version number -> 0.5.0

Version number -> 0.4.4

Add Python 3.7 and 3.8 on Travis CI

Version number -> 0.4.2

Version number -> 0.4.1

Comment test requirement; bug in flit prevents upload with it

pypa/flit#211

Version number -> 0.3.1

Release 0.3

Version 0.2