[Feature] Add support for --header wtfpl

This patch adds a header version of the WTFPL so that users can use
WTFPL in conjunction with the `--header` command-line flag.  The text
for the header links to the WTFPL site instead of mentioning the
`COPYING` file (see the link below) because there is no guarantee that
users will put their copy of the WTFPL into a file named `COPYING`.
Instead of potentially naming a non-existent file we use the
alternative version of the header text that references the official
site for the license.

Signed-off-by: Eric James Michael Ritz <ejmr@plutono.com>

See-Also: http://www.wtfpl.net/faq/
Closes: #46

lice/template-wtfpl-header.txt

@@ -0,0 +1,4 @@
+Copyright (C) {{ year }} {{ organization }}
+This work is free. You can redistribute it and/or modify it under the
+terms of the Do What The Fuck You Want To Public License, Version 2,
+as published by Sam Hocevar. See http://www.wtfpl.net/ for more details.