prototype runApp command using mozApps.mgmt API
try to runApp after manual install/update/undo an app

NOTE: currently runApp doesn't always show the app when the simulator instance
is not already running, because the homescreen is not yet fully loaded and
the app will start in background (reachable by pressing the home button to reach
the gaia tasks list)
remove unnecessary binding
fix spacing  on simulator-actors
fix remains changed appId to app in updateApp callbacks
Merge pull request #304 from rpl/feature-mozApps-runApp

change runApp command to use mozApps API and app origin