ppsave test

pep8
Merge pull request #943 from marqh/testPPSave

ppsave test
Iris v1.6 whatsnew.
Merge pull request #917 from bjlittle/whats_new_1p6

Iris release v1.6 whatsnew.
Fixed issue with derived_phenomena example expecting colorbar object to
be a tuple.
Merge pull request #952 from esc24/derived_phenom_example_mpl131_support

Fixed mpl 1.3.1 issue with derived_phenomena example
ENH: Stash code to field code translation table.
MAINT: Existing functionality maintained.

All tests will pass ensuring that current functionality is
maintained.
MAINT: Added unittests for the added functionality.
BUG: Corrected the replaced table.
MINT: Changes based on review.