In general, what is needed to add support to new boards/mcu/frameworks ? So far I've read and see in PR's - For new boards (with already supported MCU) one may follow https://docs.platformio.org/en/latest/platforms/creating_board.html and create a new_board.json as in #73 - For new framework a builder.py is needed, as in #84 - For a new atmel mcu is still unclear to me Any guideline? I want to work in adding support to SAM4 (and maybe others mcu) but i'm needing some docs