Restart app_server issues

[czeidler]

• BPicture needs to keeps a local copy of its data to be able to reconnect to a new app_server. A better way could be to use shared memory. Since the BPicture can grow, a resize function has to be implemented in the ClientMemoryAllocator. After that a similar implementation like the bitmap one can be used.

• when a app is talking to the app server while the server crashes the app may hang while waiting for a server response. Maybe improve the server link by introducing a timeout ~0.5s. If the timeout is reached, check if the app_server port really is dead and stop otherwise continuing listening.

• all the app server protocol has to be checked if messages not reaching the (dead) server are catched properly.