Simplify WakeLocks use by pushing.
Correct fault in IMAP IDLE WakeLock usage. The ThreadLocal in
MessagingControllerPushReceiver meant that the WakeLock acquired when
the DONE was sent was not being released when entering back into IDLE
state.
Consolidate the account notification so that all Activities use the
methods in MessagingController.
Look for + as acknowledgement that we're in IDLE mode, not "idling"
string.
Also, to help with battery life:
1) Give up trying to IDLE after 10 failures.
2) Increase retry delays
