Add extra stm32f0xx definitions from the old runtime
Replace exit() with _exit() in tests to avoid problems with destructing static emulator objects
Move GPIO_INIT_DEFAULTs to variant side
Enhance system_init with address offset and new subtypes
Move Register::operator& inline to allow compile-time optimisations
Add APB{1,2}ENR to RCC.h for more peripherals
Add tests/Makefile target for running tests
Add timer support (large commit)
Add analogWrite() Arduino API