Fix testing

• Switch from nose to pytest
• Switch from Travis CI to GitHub actions
• Fix broken doctests
• Fix deprecated methods
• Fix readme badges

JANAF fixes and documentation updates

v0.8.1

Bump to version 0.8.1

Fix bugs in JANAF module

Major thanks to Zach Gainsforth!

Drop support for Python 3.4

v0.7.4

Bump version to 0.7.4

Fleshed out documentation

v0.7.2

Bump version to 0.7.2

Documentation at ReadTheDocs

Add API documentation and installation instructions.

Bug fix release

Fix several bugs with Burcat and JANAF

JANAF

Merge pull request #5 from adelq/JANAF

JANAF