fw: move build to subdir
fw: add stm32vl-discovery target

Use discovery board for prototyping.
fw: switch to ChibiOS/Nil only.

And some debug stuff for VL-Discovery.
update ext libs.
fw: sync Nil configuration.
fw: commit debug code before reverting to ChibiOS/RT 2.x

Some very strange bugs with serial io in ChibiOS/Nil 3.
And we dicide move to STM32 F3 (it's only x2 price of F0 in TSOP-48, but much more
horse power).