Improvements and fixes

Dashboard tiles show the EUR value first, negative daily energy is offset against the next day, and the power graph starts without "String Sum".

• The dashboard's production, shutdown and loss tiles show the EUR value as the main figure; a switch beside the time selector puts energy first instead.
• The dashboard's energy bars set a negative daily value to 0 and offset it against the next day.
• The analysis page's power graph starts with the "String Sum" line switched off; you can switch it on in the graph's legend.