Added alpha/transparency for panels/buttons
dynamically generate text for labels
Implemented error/confirmation screens
Fully implemented calibration
added icon-offset for back button
updated formatting on button instantiation
added sudo wrapper for reboot and shutdown functions
fix comment spacing
added some documentation for calibration process
removed old comment
Merge pull request #3 from RethinkRobotics/alpha_and_errors

Added alpha/transparency for panels/buttons