Consolidated __eq__ and added missing __hash__
Merge pull request #307 from esc24/add_proj_hash

Added __hash__ to Projection
Added additonal args to TransverseMercator
Added tests
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Merge pull request #309 from esc24/tmerc_fix

Added additonal args to TransverseMercator
Merge pull request #313 from pelson/img_tile_fix

Fixed failing image tile test.
Caught case where the pcolormesh has masked pcolor values.