tests for entry and coordinate area models

test for the entry and coordinate_area models.  they are far from dry. might use contexts but I don't yet see their benefit for these. recommendations appreciated!

The files I made are "entry_spec" and "coordinate_area_spec".  The others were generated by other things.
no need to have should. Also I'm surprised this passes. use syntax

`expect(area.north).to eq(13.0)`