Split from D1287.
Adapted the template analyzer in source/tools to see if the obstructions of any building was bigger than its footprint, which would cause trouble for spawning. Elephant stables and the Ptolemy civic center needed changes. Made the Carthage elephant stable inherit like the others.
Went through the circular footprints by hand, which are awkward because the obstructions are still rectangular. They were fine except for small ships from the Briton crannog, so I used a slightly larger footprint so they'd have an easier time spawning without hitting the crannog's obstruction.

Circular obstructions: (Wonders are awkward but units have space to ungarrison on the sides.)

Crannog before and after the footprint change:

Ships spawning from docks, units ungarrisoning from ships (out the front which extends beyond the square obstruction), siege spawning from forts, units ungarrisoning from siege, and units spawning from heroes all seemed okay (although I didn't test every single combination).