Py-ART version 1.5.0

Version 1.5.0 is the result of 3 months of work by 7 contributors.
Thanks to all contributors, especially those who have made their first
contribution to Py-ART.

Highlights of this release:

* Support for reading NOXP files. (thanks to Tim Lang) 
* Support for reading ARM KAZR files (thanks to Kirk North) 
* Support for reading EDGE NetCDF files. 
* Support for reading Universal format (UF) files. 
* Refactor plotting code (thanks to Anderson Gamma) 
* Improved support for the Windows operating system. 
* Gatefilters can be used as a selection method in many additional cases (thanks to Kirk North and Nick Guy). 
* Routines for calculating circular statistics on radar fields.