Add new capability stopAppOnReset for android

Android only :  Add a capability to bring up an Android app, without stopping the process,if it is already running

Added server capability stopAppOnReset
Added capability to selendroid
Added help for stopAppOnReset
Can you add a clause explaining the "why" for this flag? Eg `Stops the app under test if it is running during the reset event. Allows yada yada in cases where dirka dirka. Default `true``.  Either something like that or add a comment  `lib/devices/android/android.js` explaining the same.


We've got a growing list of caps and we need to remember use cases down the line.