travis: Build an stm32 board with threading enabled to test it with CI.
travis: Build an stm32 board with threading enabled to test it with CI.

pozetroninc/micropython,pozetroninc/micropython,pramasoul/micropython,MrSurly/micropython,bvernoux/micropython,pfalcon/micropython,adafruit/circuitpython,trezor/micropython,pramasoul/micropython,bvernoux/micropython,tobbad/micropython,tobbad/micropython,adafruit/circuitpython,tobbad/micropython,trezor/micropython,bvernoux/micropython,bvernoux/micropython,kerneltask/micropython,pramasoul/micropython,adafruit/circuitpython,pfalcon/micropython,pfalcon/micropython,trezor/micropython,selste/micropython,trezor/micropython,selste/micropython,tobbad/micropython,trezor/micropython,henriknelson/micropython,selste/micropython,henriknelson/micropython,henriknelson/micropython,henriknelson/micropython,MrSurly/micropython,bvernoux/micropython,MrSurly/micropython,henriknelson/micropython,kerneltask/micropython,pramasoul/micropython,pramasoul/micropython,pozetroninc/micropython,kerneltask/micropython,kerneltask/micropython,tobbad/micropython,adafruit/circuitpython,adafruit/circuitpython,pfalcon/micropython,pozetroninc/micropython,MrSurly/micropython,kerneltask/micropython,selste/micropython,MrSurly/micropython,adafruit/circuitpython,selste/micropython,pozetroninc/micropython,pfalcon/micropython