save virtual sensors + list them in the left pannel
merged with gh-pages.

Merge branch 'gh-pages' of https://github.com/oscaralvaro/sn-visualization into composition

Conflicts:
	css/designtool.css
	js/designtool.js
modernizr
Merge branch 'gh-pages' of https://github.com/oscaralvaro/sn-visualization into composition