Minor fixes

Some documentation added.
Example fixed.

ATMEGA4809 / megaavr stabability and improvements

Improvements on ATMEGA4809 / megaavr implementation (Arduino Every)
some minor general fixes.
documentation

ATMEGA4809 support

Since Version 1.5.0 the original ATmega168 based implementation was refactored and enhanced to support also other processor architectures like the megaavr ATMEGA4809 that can be found on Arduino Every and Arduino WiFi Rev. 2.

DMXProbe

DMXSerial now supports the DMXProbe mode.

• Retrieve one DMX packet at a time
• stop interrupts after receiving
• new sample: drive NeoPixel and WS2811 chips

1.3.0

Enabling changing the DMXModePin as an optional parameter to the init function.

1.2.0

Stable Version 1.2.0 Arduino Library Manager compatible.