Pseudonetcdf

This version has several new features and fixes. The most notable update is the xarray plugin. This supports pseudonetcdf via xarray, which was previously in xarray. Now, that functionality is in pseudonetcdf, but the difference is seamless to the user.

Other fixes include from minor updates on v3.2.3 include:
* pyproj import in wrfioapi is fixed.
* the uamiv writer is more robust
* the type comparisons were all updated to isinstance
* and ioapi auditing now works with bcon files.
* GRIDDESC files no longer need to be space delimited and have ' ' section separators

What's Changed
* Updating tomsl3 and cdtoms by barronh in https://github.com/barronh/pseudonetcdf/pull/131
* Feature/var from array by barronh in https://github.com/barronh/pseudonetcdf/pull/132
* Enhancement/flake8 by barronh in https://github.com/barronh/pseudonetcdf/pull/133
* Updated val2idx to fix bounds warning by barronh in https://github.com/barronh/pseudonetcdf/pull/134
* Bugfix/griddesc gdnam none by barronh in https://github.com/barronh/pseudonetcdf/pull/136
* Fixing GDNAM in griddesc and adding tests to prevent recursion errors like those in PR 136 by barronh in https://github.com/barronh/pseudonetcdf/pull/141
* Bugfix/gcnc ll2ij by barronh in https://github.com/barronh/pseudonetcdf/pull/142


**Full Changelog**: https://github.com/barronh/pseudonetcdf/compare/v3.2.2...v3.2.3

Recursion bug fix. This bug only affects v3.2.1 and this is a day 0 fix.

This update includes a lot of new testing capability, version awareness, and a bugfix for ioapi VAR-LIST.

* testing capability: moving to `tox` as a way of performing isolated build and testing locally to limit dependence on Travis-CI.
* Added `__version__` attribute and version.py. This will only work when the software is installed, and is similar to the xarray implementation.
* VAR-LIST is supposed to rebuild when VAR-LIST is missing or set to a zero-length string, but was broken in the last release. This version includes a bug fix and adds a unit test to ensure this doesn't happen again.
* An artifact of testing was also removed.

The move away from Travis-CI was in response to updated billing practices. Originally, PseudoNetCDF needed approval for an open source account. After that was obtained, I still can't trigger builds.

This update includes several general improvements.

Specifically, the ioapi interface ahs been improved to keep meta data up to date, but also to add an audit function. The audit is useful for checking the "correctness" of the ioapi metadata. There were also significant improvements to the griddesc interface to ioapi.

Separately, there were bug fixes to address insertDimension problems and remove deprecations.

It became clear that several functions were repeated in code and should be promoted to methods. These methods were needed and developed for the following utilties:
* https://github.com/barronh/aqmoco
* https://github.com/barronh/aqmbc
* https://github.com/barronh/evalwoudc
* https://github.com/barronh/evalhaze
* https://github.com/barronh/cmaqsatproc
* https://github.com/barronh/cmaqpandoras
* https://github.com/barronh/gadm2ioapi

This release brings the standard version of PseudoNetCDF up-to-date with utilities.

In addition, several bug-fixes were made for CMAQ-related utilities and GEOS-Chem's new NetCDF formatted files.