First step towards localized version of the visualizations

This only deals with the stats page so far and only adds a German version.
Additionally it does on the fly conversion to metric.

Right now for simplicity these settings are implemented through URL arguments -
&metric=true switches to metric, &lang=de switches to German.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Force language to be lowercase

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Localization of energy graph

Adds support for German and for metric data. Some of the dates are still shown
US style (the x-axis of the graphs).

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Remember metric and language settings across links

When switching between energy and stats we now keep these settings.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Merge pull request #55 from dirkhh/localization

Localization