Add copyright notices to each file

[flbulgarelli]

Add the following copyright notice to each platform's file:

Mumuki-Platform - the hearth of the Mumuki Project 
Copyright (C) 2014, 2015  The Mumuki Project

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

[flbulgarelli]

We should check if there is any automated tool that does this for us or enforces it.

[faloi]

Again, are you really sure this makes sense?

[flbulgarelli]

I think this makes sense will all GPL components - atheneum, classroom-api, bibliotheca.

https://www.gnu.org/licenses/gpl-howto.html

I have not seeing this practice enforced in other people's gems, but they are MIT, so it is less important.

[flbulgarelli]

Are you really sure this makes no sense?

[faloi]

Nope, but given this change is not free, I think we should really evaluate whether it's necessary.