use direct connection to prevent a crash with sender being garbage in onSignalEmitted

Running into a persistent crash as noted here: https://github.com/KDAB/GammaRay/issues/88

Using Qt 5.2 32-bit with a 32-bit i686 injector on OS X 10.10 x86_64.  Seems that onSignalEmitted's sender is garbage sometimes.  Quick fix is to use a DirectConnection to invoke the method instead of an AutoConnection.

With this fix in place, I'm able to actually launch GammaRay and browse the object hierarchy of my application.