change em bin file to em.js

 On branch master

	deleted:    bin/em
	new file:   bin/em.js
	modified:   package.json
remove coffeescript and improve REPL

 On branch master

	deleted:    lib/cli.coffee
	new file:   lib/cli.js
	deleted:    lib/repl.coffee
	new file:   lib/repl.js
updates to dependencies, manage script

 On branch master

	modified:   .gitignore
	modified:   manage.sh
	modified:   package.json