changed loader for fxml to use contextclassloader, will change to assetloader later

renamed initialize to precache due to clash with @FXML initialize()

Signed-off-by: Kai Börnert <kai-boernert@visiongamestudios.de>
allow to retrecieve the controller of the loaded fxml

Signed-off-by: Kai Börnert <kai-boernert@visiongamestudios.de>
replaced DefaultCursorProvider with ProtonCursorProvider
Changed test page to acid3 test to show the embeeded browser finishes it
fixed invalid maxHeight&maxWidth for test screen.

Signed-off-by: Kai Börnert <kai-boernert@visiongamestudios.de>
merge with heiko + adjustments for changes since his branch
added a few missing cursorTypes

Signed-off-by: Kai Börnert <kai-boernert@visiongamestudios.de>
Integrated latest changes from empire phoenix upstream rev:29