Support HPLN/HPLT
avoid adding and subtracting transData if not needed
Added RTD pip requirements file
Don't apply rc parameters, otherwise only first plot appears
Implement s.sss and m.mmm formats
Ignore '-' when looking for duplicate characters in tick labels. Fixes #17.
Allow custom longitude wrapping. Fixes #16.
Improved separators for degree angles.
Fix tests with all Python versions
Fix test failures
Use private fork of matplotlib with fixes to plot_directive
Make use of new :context: reset
Added six to requirements
Use a standalone version of plot_directive
Don't set font for docs
Use setuptools if available
Add missing loop
Allow reseting wcs object
Merge pull request #21 from ChrisBeaumont/master

Small tweaks and bugfixes
Re-implement set_[xy]label