Release 2020.16.0

Bugfixes and improvements on various parts of OpenEMS:

• RRD4j: local timeseries database
• Ess Sell-To-Grid Limit Controller: increase charging of battery to avoid 70 % cutoff
• OneWire: temperature sensors
• Controller.Api.Rest: local JSON/REST Api
• Controller.CHP.SoC: control of a CHP or diesel generator based on State-of-Charge
• special handling required for charging of Renault ZOE

https://github.com/OpenEMS/openems/releases/tag/2020.16.0