Remove copyright lines and the LICENSE file.

These will be replaced with a new version that refers to an AUTHORS
file. The AUTHORS file approach is far superior, as you can add an
author by simply adding a line to one file, instead of fixing all of
the comments.
Add new copyright lines to source files, LICENSE file, and AUTHORS file.

Fixes #11
Merge pull request #20 from eaburns/dev/license

Change author and license info to refer to an AUTHORS file.