Release 6.6

• Support firmware version 6.6.
• Add operating mode configuration options on the thermostat configuration screen.
• Add new message IDs for remote override HC2, cooling hours, power cycles, and brand information.
• Collect brand information strings in capability log, if supported by the PIC firmware.
• Include graph span in the configuration file for easier modification.
• Make the web graph duration match the configured span value.
• Fix error from update via cli.
• Make update from cli work without the need for a boiler to be attached.
• Fix MQTT actions (issue #23)
• Fix error from web server configuration tab when running in docker as user.
• Fix upgrade using a hex firmware file created on Windows.