add nvd3
add streamgraph widget
add simple leaflet map widget to dashboard
update streamgraph with pseudo live data
Merge remote-tracking branch 'upstream/master'

Conflicts:
	visualization/app/assets/javascripts/application.js
	visualization/app/assets/stylesheets/application.css
	visualization/app/views/widget/index.html.haml
	visualization/vendor/assets/javascripts/nv.d3.js
	visualization/vendor/assets/stylesheets/nv.d3.css