Add styles for rickshaw charts

Conflicts:
	app/assets/stylesheets/admin/styles/plugins/_rickshaw.scss
	app/assets/stylesheets/admin/styles/sections/_hub_dashboard.scss
More work on graph styles

Conflicts:
	app/assets/stylesheets/admin/styles/sections/_hub_dashboard.scss
Adds Dashboard specific styles (CSS)
Uses hub_dashboard.scss instead stats.scss

Conflicts:
	app/assets/stylesheets/admin/styles/sections/_hub_dashboard.scss