Default NetCDF dimensionless unit.
Lazy data.
Review fixes.
Factor out test message creation.
Deprecate `auto_regularise`.
Minor review actions.
Data -> Message
Merge pull request #7 from bjlittle/minor_change

Minor review actions.
Merge pull request #1322 from rhattersley/lazy-grib-data

Lazy data for GRIB.
Various GRIB2 fixes.
Ignore the top two bits of the scanning mode.
Merge pull request #1329 from rhattersley/grib2-fixes

Various GRIB2 fixes.
Merge remote branch 'bjlittle/default_netcdf_unit_dimensionless'

Conflicts:
	lib/iris/tests/results/usecases/pp_to_cf_conversion/from_netcdf/aaxzc_n10r13xy.b_0.cml
Merge pull request #1330 from rhattersley/grib2-scanning-mode

Scanning mode 64/128 for data
numpy array optimisation of _quadrant_area
Merge pull request #1319 from jkettleb/area_weight

Optimisation of iris.analysis.cartography._quadrant_area
Ignore/warn the data-cutoff time.
Merge pull request #1332 from rhattersley/grib2-data-cutoff-ignore

Ignore/warn the data-cutoff time.
First rework working pdt0
Rework + add first attempt pdt8 support.