[comment addon] Implement automatic commenting/uncommenting

addon/comment/comment.js

doc/manual.html

mode/clike/clike.js

mode/clojure/clojure.js

mode/coffeescript/coffeescript.js

mode/commonlisp/commonlisp.js

mode/css/css.js

mode/erlang/erlang.js

mode/gas/gas.js

mode/go/go.js

mode/haskell/haskell.js

mode/javascript/index.html

mode/javascript/javascript.js

mode/lua/lua.js

mode/ocaml/ocaml.js

mode/php/php.js

mode/python/python.js

mode/ruby/ruby.js

mode/rust/rust.js

mode/scheme/scheme.js