Update to showSite() to launch without going via shell and retain pid of process
Fixes and improvements to ensure launched chrome is brought to front and activated on OS X and Linux. Linux still requires testing.
Fix for fullscreen/kiosk issue on linux where it takes full screen but leave black bars down side/bottom due to not maximising underlying surface.
Load url via a temp black background file to minimise white flashing at chrome startup. Not perfect on OSX during maximising to fullscreen phase.