js: Fix problems with subscriptions and large int32s
Move navigator and ui props into sub probs in global space

navigators now reside in

 $global.navigators.

and user interaces in

 $global.userinterfaces.

There is also a symbolic link $global.navigators.current that
links to the currently focused navigator on the primary UI
js: Remove some ugly hacks related to property subscriptions
js: Add an example for subscriptions