[airborne] move print.h to subsystems/datalink/uart_print.h
[airborne] removed unused and obsolete micromag
if the micromag sensor itself is still needed/used,
update the mag_micromag_fw module to use new spi subsystem
and make it arch/firmware independent
[fixedwing] remove extra joystick c file and move header to fixedwing dir
still ugly though...