2.1.5
This release contains no functional changes other than changes to the Appveyor configuration for publishing wheels.
2.1.4
This release contains no functional changes other than changes to the Travis configuration for publishing wheels.
2.1.3
A simplification of the tox.ini file
More robust checking for pkgconfig availability
Integration of cibuildwheel into travis builds so as to build and publish binary wheels for Linux and OSX
Only require pytest-runner if pytest/test is being called
Blacklists version 3.3.0 of pytest which has a bug that can cause the tests to fail.