* lib/rake/doc/MIT-LICENSE: Add license file from upstream
* lib/rake/doc/README.rdoc: Link to license file from Rake README
* lib/rake/version.rb: Include README rdoc for Rake module overview


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39193 b2dd03c8-39d4-4d8f-98ff-823fe69b080e