Added unlockEmulator to unlock the emulator during emulator-start

Added code to unlock the emulator after it is started via emulator-start

The unlocking is controlled via a new boolean parameter (unlockEmulator) that is defaults to false for backwards compatibility.
See the following stackoverflow answer from Yimin Li to see where I got the event keys to send to the emulator.
http://stackoverflow.com/questions/1959012/how-can-i-unlock-the-screen-programmatically-in-android