Remove reference to missing html5-haml template

This template is not shipped with Middleman as of 3.0.12.
Merge pull request #161 from Odaeus/patch-1

Remove reference to missing html5-haml template
Update built-using-middleman.html.erb
Merge pull request #162 from recrea/master

Add Quaderno to middleman sites list
Merge remote-tracking branch 'upstream/master' into ja

Conflicts:
	source/getting-started.html.markdown