Add CommonJS license to dist

Technically this should probably not be necessary: Duktape module loader
is a fully own implementation based on the CommonJS module loading
specification.  The specification is not shipped with the distributable,
just the master repo.  But it's perhaps best to mention it in the README
still.
Merge branch 'add-commonjs-license-dist'
Use duktape.org instead of www.duktape.org
Merge branch 'website-link-trivia'
Add link to compiling info to dist readme
Merge branch 'compiling-link-to-readme'