Change charge chart to line chart and move to energy page

This seems to make much more sense - the trip page has daily summary
information - the charge chart with minute granularity didn't fit in with that.

In the energy chart on the other hand this is all now nicely aligned and gives
a reasonably complete picture.

Also, displaying current and voltage as lines instead of bars is much more
intuitive. Added the hovering tooltip gives us the kW, too.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Change stats / trip tp "Daily Summary Chart"

And try to use that consistently :-)

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Interrupt Wh/mile line for days with no driving

Continuing the line through those days gave the wrong visual impression.

In order for this to work I had to hix the flot.orderBars plugin as that did
not deal well with line graphs with null segments as part of the data series.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Better align the different graphs on the Energy page

Missing data could create very odd looking charts that were visually confusing.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>