Cleaned up a bit of the broadcasting code.
Made everything use turf's z levels as I find them more reliable, sometimes an item's loc can be null or the z level can be entirely wrong. I hope the high usage of get_turf() will not create problems.
git-svn-id: http://tgstation13.googlecode.com/svn/trunk@4275 316c924e-a436-60f5-8080-3fe189b3f50e