surfaceflinger, multiwindow

[krnlyng]

• we use surfaceflinger.
• multiwindow has some issues
  • if an app is started which was already started it will cause window recreation in renderer because there seems to be no api to bring a window to the front (see systemui #3)
  • if an app is started there might be lag where nothing is drawn
  • we use am.jar to start/stop apps. TODO: use a socket connection to android