delete unuse HandleBackKeyPress

1.in xface 3.2,BackKeyPress events dirtectly handle by CordovaView
modify hide splash handle & SystemTray visible = false;
remove duplicate ResolutionHelper.cs file
update wp8 splash

1. delete wp8 system show splash
2. add 1080p splash
update config.xml

1.delete unuse preference
2.support fullscreen preference (show/hide systemTray)
3.update hidesplash after defaultapp loadcompleted