Implement export for groups line graphs.
Implement export for groups line graphs.

OpenEnergyDashboard/OED,beloitcollegecomputerscience/OED,OpenEnergyDashboard/OED,OpenEnergyDashboard/OED,OpenEnergyDashboard/OED,beloitcollegecomputerscience/OED,beloitcollegecomputerscience/OED,beloitcollegecomputerscience/OED