Few fixes with persistent authentication

[daymondm]

• Initial login will continually retry until it is successful. Previously if the login failed, the error was uncaught and homebridge would exit. (i.e. if internet connection is currently unavailable)
• Fixed issue when battery level = 0
• Removed duplicate if statement for motion sensor
• Fixed redundant notification when garage door closes
• Fixed promise setter function to debounce changes with dimmer switches (experimental - no devices available to test)