Support for Arduino SERCOM and fix for STM32 begin.
Add support for custom SERCOM interface of Arduino SAMD devices.
Force SDA SCL to use GPIO numeration for STM32 bug (https://www.mischianti.org/forums/topic/compatible-with-stm32duino/).
Add support for custom SERCOM interface of Arduino SAMD devices.
Force SDA SCL to use GPIO numeration for STM32 bug (https://www.mischianti.org/forums/topic/compatible-with-stm32duino/).