More reliable setup and split event managers.

Don't rely on javascript file order when upgrading and setting up
views/models. Instead, successively trigger setup signals on a local
vent (ListIt.lvent). To handle asynchronous setup methods, provide a
lock when triggering signals that will block setup until released.

This commit also splits the global vent into gvent and lvent. lvent
should be used for window-local events (setup etc.) and gvent should be
used for global events.