Make sure kibana and grafana on same hostname do not interfere with each other

This happens if you have kibana on /kibana and grafana on /grafana, resulting in some bad redirects

added nonNegativeDerivative function

simplified a lot of the time series data manipulation prior to handing it to flot, kibana used a lot of code to sort and make sure all time points needed had values, this is not needed for graphite time series data. Fixes som strange issues with "null point mode" and inconsistent rendering between graphite and grafana flot,

basic authentication added for elasticsearch