Move stm32 HAL implementation in backends folder.
Merge branch 'master' of https://github.com/r-3-t/embedded
Fix integer overflow on clock delay for stm32f1x and stm32f4.
Fix namespaces resolutions in stm32f1 gpio and spi.
Move HAL path from stm32f100.cmake and stm32f103.cmake to embedded.cmake.
Add a new frontend for arduino.
Add arduino blink led example to board examples.
Fix sleep delay name : usleep (µs) is now renamed to msleep (ms).
Fix HAL BASE cmake variable for stm32f104 projects.