This way scripts on pages don't have access to it.
Exception is qupzilla: scheme as internal pages requires the bridge.
GreaseMonkey userscripts now runs on ApplicationWorld too. This fixes
userscript that depend on script world being isolated from main page world.
Tested with 4ChanX + OneeChan.
This is first quick port to QtWebEngine, most of advanced features
are not working yet. Please read README.
For now, it will use separate profile directory as well as browser
session, that means you can use both QtWebEngine and QtWebKit versions
at the same time.
