Add an optimisation for single valued coordinate constraints.
Fix to license check logic
Merge handles string coords.
Updates to erroneous copyright years based on git history.
Fixed copyright date of an experimental file.
Merge pull request #486 from pelson/license_header_check

Fixed copyright date of an experimental file.
Merge pull request #475 from bjlittle/merge_strings

Cube merge string coords.
Merge pull request #487 from esc24/licence_fix

Fix to copyright licence check logic.
fixed netcdf save cubelist bug
Cope with non-numeric/Cell values.
Area weighted regridding.
Merge pull request #488 from cpelley/fix_netcdfsavebug

Fixed NetCDF saving of special case of CubeList.
Update licence dates.
Merge pull request #428 from rhattersley/constraint-speed

Add an optimisation for single valued coordinate constraints.
Update categorical coordinate names to match function names.
Warn on deprecated defaults and deprecate the aliased functions.
Merge pull request #480 from rhattersley/unambiguous_season_year_naming

Unambiguous season year naming
Review actions.
PEP8 corrections to iterate.py.
Merge pull request #464 from esc24/area_weighted_regrid

Area weighted regridding