Added bash script to add GPL statement to the top of every source file

Added newlines to the end of copyrightJava.txt and copyrightXML.txt to make things pretty. 

Wrote a bash script to add our GPL statement to the top of all of our source files.

I've tested the script on a dummy checkout of our source and it works. I'm putting this pull request up now to make sure I haven't missed any of our source files. Actually running the script and pulling in the changes will be left for another pull request.