[CF-metadata] new map projection

[Jonathan Gregory]

Dear Magi

> I would like to propose the Lambert Azimuthal Equal-Area map projection
> for inclusion. This projection has the following parameters:
> grid_mapping_name = lambert_azimuthal_equal_area
> longitude_of_central_meridian
> latitude_of_central_meridian
> false_easting
> false_westing

Should it be latitude_of_projection_origin, like many other projections, rather
than latitude_of_central_meridian? FGDC has latitude_of_projection_origin for
this projection.

Jonathan