Improve GLSurfaceView to avoid deadlocks and race conditions.

This is work towards fixing bug 2228262

Specific issues fixed by this change:

+ GLThread names now include the thread id, making it easier to tell one
GLThread from another.

+ A private final static boolean LOG_THREADS can be set to true at compile
time to print out thread-related trace information, helpful for debugging
GLSurfaceView behavior. This static defaults to "false".

+ Changed calls to "notify" to "notifyAll" to make the code more
robust in case more than two threads are blocked on the same monitor.

+ Add a GLThreadManager to help manage the transition to
a new GLThread. Currently only one GLThread can be active in an address
space. When the second thread starts up, the GLThreadManager helps the old
GLThread to shut down,

+ Make sure we stop waiting for dead GLThreads. This is done by adding
checks for a variable mDone being true to our monitor wait loops. And
we use a "finally" clause at the end of GLThread.run() method to set mDone
and notifyAll any wait loops.