Fix the handling of screen orientation changes. In these cases almost the entire application is tor…

Fix the handling of screen orientation changes. In these cases almost the entire application is torn down, which includes the destruction of the VMGlue instance. When we restart we create a new VMGlue but we don't want to reinitialize the VM, just create a new main isolate.

Also in the CL, I added a dependency of the .apk on the embedder library, so that I can rebuild the apk after a library change without having to start from scratch.
Committed: https://code.google.com/p/dart/source/detail?r=19510

[vsm, 2013-03-05 19:46:58]

lgtm

[gram, 2013-03-05 19:50:36]

Committed patchset #1 manually as r19510 (presubmit successful).