mod_admin_stats: fix fill-opacity after loading
mod_admin_stats: live updates of histogram charts.

Work in progress. Currently updates on the push of a button.
Also removed the now unused nvd3 lib.
mod_admin_stats: cleanup.

Got rid of javascript variables. Use wire's to hook everything up.
Renamed the request/response notify/event pair to 'update_metrics'
and 'new_metrics' resp.