Add shape of earth 1 and 7

This PR extends `ellispsoid` to handle `shapeOfTheEarth` value `1` and `7`.

This is a precursor to GDT 4/5.
Not your fault but..
I think this shows a bug with the definition and use of ```_CODE_TABLE_3_2_SHAPE_OF_THE_EARTH_RANGE```.
This is defined as 9, but 9 is actually *not* a valid value.
So if you pass 10 you will get an "invalid shape of the earth" message instead of "unsupported", but actually 9 should do the same.
Personally, I'd ditch the range test and just call anything unrecognised 'unsupported', which also sidesteps the question of how it is viewing MDI/255 and any possible negative values (presumably excluded, but no clear statement as per usual).