Update `CONTRIBUTING.md`

* Remove extra `the`.
* Remove IRC reference as it does not help the user in
  any way, plus, we don't have an official IRC channel.
Merge branch 'master' of github.com:h5bp/html5-boilerplate

Conflicts:
	CONTRIBUTING.md
Less update
Update bootstrap.min.js
Remove template and less code
Merge branch 'master' into template

Conflicts:
	index.html
	less/main.less