Fixed a bug where trying to write SBUS packets with Teensy 3.1/3.2 wo…

…uld hang the processor by de-referencing a null pointer

Updated core to v3.1.3

Updated core to v3.1.2

Updated core to support MMOD

Added option for fast SBUS (200000 baud)

Enabling ESP32 to use non-inverted SBUS

Fixed bug in SBUS timing, added options for non-inverted signals, and…

… simplified the class interfaces.

Using std::array for passing around SBUS data and commands

Cleanup after merge. Using mcu-support repo for CMake builds.

Removed the tools folder to fix Arduino linting