SSP-682 Require value between 0-16 for highest grade completed.

13 would probably have be a reasonable upper bound that would accommodate
most domestic and European users. But went with 16 as an attempt at a
compromise between being accidentally over-restrictive and allowing total
nonsense.

Should be identical to 2a3f4d4 bit with aggregated/minified JS
regenerated (so the conflict was meaningless).

Conflicts:
	src/main/webapp/app-all.js