Remove/deprecate jQuery 1.9 boxModel externs

$.support.boxModel deprecated, $.boxModel removed since 1.8:
https://github.com/jquery/jquery/commit/c4e22ad8b5edd52ac78ec44bf7df8a7f37403623#diff-6d4bb79610683d9749d2cbb62e708d88
http://api.jquery.com/jQuery.boxModel/

Fixes google/closure-compiler#159
Various corrections to jQuery 1.9 externs

Corrects a number of signatures to actually match the jQuery 1.9 API,
and adds helpful messages to many @deprecated tags.

Fixes google/closure-compiler#158