Esc key doesn't work at Opera

How to reproduce: you cannot use Esc key for closing a thickbox window while using Opera. X and C keys work as should.

Reason: vanilla thickbox.js was affected somehow and differ from Thickbox author's js while having the same release number.

How to fix: change to strings at thickbox.js

-          else if ($.browser.safari) { // safari
+          else if ($.browser.safari || $.browser.opera) { // safari OR opera

Patch is attached.