#120 Frontend improvements: Data refreshing not working properly

[AuxiliumCDNG]

Relates to #120
There seems to be an issue with the error handler or something in the call structure when new data should be drawn into the charts.
There is some weirdness where the error box disappears but the charts don't show up and the charts are also not updated correctly every time.

Please help @fabiancdng

[fabiancdng]

@AuxiliumCDNG No issues for me, fetching the data and drawing the charts seems to work just fine (even when changing the date range or using the site on my phone)...

[AuxiliumCDNG]

Both error box and old data visible (daterange set to 1st til 10th Jan).

Happened when selecting daterange with no data in it.