Fixes throughout the app

* Removed the holder class in SensordroneControl (we handle orientation changes ourselves, in this case it means that we do not restart, android:configChanges="orientation" on activities handles this, see the manifest file)

* Made all alertinfo methods static since we do not need to hold the activity and we can just pass it to methods when we want to display an alert (text should be moved to string resources though...)

* Moved some layout params etc to XML files where they belong

* Other small fixes throughout the app