What's Changed
* Updated to IGRF-14 model by nickssl in https://github.com/spedas/pyspedas/pull/1108
* Set min time of IGRF model to 1965 (previously, it was 1970) by nickssl in https://github.com/spedas/pyspedas/pull/1113
* Added minvar_matrix_make outputs for eigenvalues and basis vectors
* xyz_to_polar now works on tplot variables
* Updated required version of pytplot-mpl-temp to support wildcards in many utilities (options, ylim, zlim, time_clip, deflag, degap...)
* Updated several test suites to exercise updates to minvar_matrix_make, xyz_to_polar, tplot variable wildcards
* Updated documentation on pyspedas.readthedocs.io
**Full Changelog**: https://github.com/spedas/pyspedas/compare/v1.7.6...v1.7.7