Added support for UM fieldsfile ancillary files trunkated with ieee.
Merge pull request #740 from pelson/ancillary_ieee_32

Added the magic lines to support UM ancillary files trunkated with the UM utility ieee.
Corrected 'temperature' var name to 'air_pressure', plus a couple of PEP8 changes
Respect major/minor axes when converting to Cartopy.
Merge pull request #748 from rhattersley/fix-geogcs

Respect major/minor axes when converting GeogCS to Cartopy.
Upgrade GeoTIFF export.

Add support for various data types.
Add support for coord systems.
Map 0 to 360 longitudes into the -180 to 180 range.