This is more or less an update of #711 as it's heavily outdated and has been dragged along through the merge windows for a while now. Unfortunately I had to redo all of the work because there were a lot of files that had been moved since that PR.
This updates the GPL header to avoid providing an invalid address of the FSF and also updates the (C) year dates.
Disclaimer: I have not done any manual work, this is all Find & Replace so I'm 100% sure that I missed files that might have no GPL header at all. Furthermore I only really processed files in the "xbmc" directory. Wasn't sure what to do with any files in "lib" etc but it's certainly better than nothing.
fix address line in GPL headers
update date in GPL header
Refresh sections after myplex login event.