Add licence to repo, copyright notices to source files

[gerth2]

This is not a huge priority, but probably should be done before we make the codebase public.

We should at a minimum add a licence to this software, since it will be open-source. I'd put in a vote to use the MIT licence - it's pretty non-restrictive, which makes it nice for other teams or organizations, but does make sure we aren't liable for the behavior of our software if someone trys to take and use it in some other way ("provided 'as-is'").

Additionally, I think it would be a good idea to add the following header of information to each source file:

/*
 *******************************************************************************************
 * Copyright (C) 2017 FRC Team 1736 Robot Casserole - www.robotcasserole.org
 *******************************************************************************************
 *
 * This software is released under the MIT Licence - see the license.txt
 *  file in the root of this repo.
 *
 * Non-legally-binding statement from Team 1736:
 *  Thank you for taking the time to read through our software! We hope you
 *   find it educational and informative! 
 *  Please feel free to snag our software for your own use in whatever project
 *   you have going on right now! We'd love to be able to help out! Shoot us 
 *   any questions you may have, all our contact info should be on our website
 *   (listed above).
 *  If you happen to end up using our software to make money, that is wonderful!
 *   Robot Casserole is always looking for more sponsors, so we'd be very appreciative
 *   if you would consider donating to our club to help further STEM education.
 */