License the project clearly

License the project clearly

This adds a LICENSE file that describes which licenses this project is
licensed under. This is very important, as the project is licensed under
three licenses.

Also added are copyright notices to the wscript files. I added myself as
copyright holder to them, but there are other people who have
contributed to these files which should have their name in the copyright
header. Clearly stating the license of the wscript files should have
been done long ago.