Default NetCDF dimensionless unit.
progress
Add lightweight grib wrapper
Review actions: docstring improvements and more
Correct pep8 failure that slipped through
Further review actions
Tests tweaks
Fix string formatting bugs in STASH object error messages.
Add another get key value special case
Add pp constraint conversion test where STASH=stash-object (instead of string).
Allow STASH-constraint conversion where reference is a STASH object (instead of a string).
Removed patch awareness from test
Fix a comment typo. No code is changed in PR!
Merge pull request #1310 from ocefpaf/fix_typo

Fix a comment typo.
new metarelate api
Merge pull request #1303 from dkillick/lightweight_grib

Add lightweight grib message wrapper
ENH: Added lazy aggregator support for STD_DEV
Merge pull request #1297 from cpelley/lazy_stdev

ENH: Added lazy aggregator support for STD_DEV
Hide new API.

Change from:
    iris.fileformats.grib.GribMessage
to:
    iris.fileformats.grib.message._GribMessage.
Use both _GribMessage() and _RawGribMessage().