FEAT: Added `pi` word definition.
FEAT: added new compilation option: ABI (for selecting a specific ABI when needed).
FEAT: added new RPi compilation target.
FEAT: hard-float (armhf) ARM support added.

Set the right ABI for ARM targets in config.r when needed:
    ABI: 'hard-float
will set the armhf mode instead of the default armel.