Fix all of the include guards for all of the headers.

Also fix copyright statements in headers.
I can see where you are coming from and I don't intend to be critical :blush: - it's just that technically the person who created the file gets to say what the licence is; now it's not ever been in doubt that Mudlet is GPL (and for it to be hosted on the public part of github I believe it HAS TO have that sort of licensing) and so it probably isn't unreasonable to assume that someone putting forward some piece of code to be included does so with such licensing to be intended - but for strict compliance to FSF standards we should be able to prove it, which is why the template headers are there, or so I understand. On the other hand I ANAL... :smile: