conditional.mk: fixes
open407vc platform: basic build, ivory Platform support, toy app blinks leds
smaccm-mavlink: working on a better debugger
hwf4 tests: only build for px4fmu17_freertos
makefile: default build is for platform CONFIG_DEFAULT_TARGET

* make it easier for someone developing for another platform...
ivory-bsp-stm32f4: implement GPIO pinRead
smaccm-mavlink debugger: fixup
open407toy: started implementing pin debouncer

* need to change up some statemachine semantics to make it work