Feature enc x24 j600 wip

- Adding classes Register_GPIO_BSRRL & Register_GPIO_BSRRH and modifying GPIO.h
- Adding objects for Register_GPIO_BSRRL & Register_GPIO_BSRRH in emulator.mk
- Now, all the RF tests works fine with ellduino, stm32f4discovery & stm32f334nucleo
Please don't do these changes of replacing the macros with plain keywords.  The macros are useful as documentation, even though they always expand in the same way.