Bug 862540.  Make window.status actually be settable (but have no effect unless the pref that no one ever sets is set).  r=smaug
Bug 862917.  Remove the non-standard window.defaultStatus.  r=smaug,gavin
Bug 863386.  Add support for nullable enum arguments and return values. r=mccr8

This incidentally fixes bug 843355
Bug 862077.  Even if we have a wrapper cache, don't assume that no cached wrapper means no wrapped native.: it's not true for inner windows.  r=peterv
Test for bug 862702.  r=peterv