Implement a new addAllGlobalsAsDebuggees method for faster chrome debugging (bug 821701); r=jimb

Also GC only once when going through all compartments in both addAllGlobalsAsDebuggees and removeAllDebuggees, instead of once for every debuggee added or removed.
Bug 826180 - No stylesheets shown after reloading a page with an iframe; r=paul
Bug 826563 - CSS validation errors in toolbox.css. r=paul
Bug 824487 - Transition event callbacks sometimes don't fire, r=rcampbell