What's Changed
* Example of adding external FO to an observation by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/45
* Stats module tests by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/47
* Small doc fixes by mjs2369 in https://github.com/NCAR/pyDARTdiags/pull/48
* test for bin layer in height by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/50
* skip the columns created by stats & bin by level when writing obs sequences by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/51
* Unit conversion for pressure only by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/52
* used observations should include QC=2 by lkugler in https://github.com/NCAR/pyDARTdiags/pull/54
* fix: stats module used observations should include QC2 by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/56
* Observation sequence write fixes for header types and num_obs by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/59
* Composite observations (e.g u,v wind) testing improvements by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/60
* Fix used obs in matplots by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/62
* Grammar and typo fixes, and links to statistics documentation in the examples by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/64
* Plot evolution by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/67
* add pytest coverage to requirements for developers by hkershaw-brown in https://github.com/NCAR/pyDARTdiags/pull/69
New Contributors
* mjs2369 made their first contribution in https://github.com/NCAR/pyDARTdiags/pull/48
* lkugler made their first contribution in https://github.com/NCAR/pyDARTdiags/pull/54
**Full Changelog**: https://github.com/NCAR/pyDARTdiags/compare/0.5.0...0.5.1