Using GPIOA_IDR directly looks a bit arcane, and the example can benefit
from introducing gpio_get() and how to use it. The stm32f0-discovery
example already does it like this.
Be specifically careful with the usb examples. There is likely some
breakage to be expected, not sure I updated all the drivers to the
correct types for the respective chips.
Replace includes of stm32/YY/xxxx.h with stm32/xxxx.h
Replace stm32/YY/nvic.h with cm3/nvic.h.
In some cases, the include list was resorted alphabetically when it was
complicated and I was reviewing them manually, but most of this was
automatically done.
