Adding ability to specify -installedApp on command line.

Allows one to run tests locally without having the standalone server install an app every time.
some responses don't return a value all the time (like execute script without 'return')
changing the interface to pass the AndroidApp instead of a string to the apk file.

adding some printstacktraces to attempt to troubleshoot errors that happen on the server
(it's not nice to swallow errors anyways)
Logging output from any executed process
printing out exec sync output to help with debugging
adding retry logic for starting emulator
adding retries to starting instrumentation
adding logging for finding device
retry killing the emulator until it is really dead
handle killing emulator gracefully. kill adb server after 10 seconds of it starting up