Added a settings screen that allows the user to define coordinates of
the cameras and reflectors on the calibrator.  All settings are saved to
"settings.txt", and settings are loaded each time the settings screen is
opened so that the user can see current stats.  

Created a public static function readSettingsFile() that returns an
array of the coordinate values, so that we can access the settings from
anywhere in the program without having to copy code.  Order of
coordinates is as follows:
 - Camera 1
 - Camera 2
 - Camera 3
 - Center reflector
 - Left center reflector
 - Right center reflector
 - Top center reflector
 - Bottom center reflector
 - Top left diagonal reflector
 - Bottom left diagonal reflector
 - Top right diagonal reflector
 - Bottom right diagonal reflector
 
 
Also made small, various updates to other screens.