digital/io-hub/src/apbirthday: adjust cake follow mode distance
host/simu/model: real US sensor vision angle is not that large
digital/io-hub/src/apbirthday: fix bad !d command
digital/io-hub/src/common-cc: also report obstacles expiration
digital/io-hub/src/apbirthday: also accept demo after actuators init
digital/io-hub/src/common-cc: conditionally remove unused states after 566f78ca
digital/io-hub/src/apbirthday: temporarily disable unused FSM
digital/ucoolib/ucoolib/dev/xmodem: add simple xmodem receiver
digital/io-hub/src/bootloader: add io-hub-stm32 XMODEM bootloader

Not exactly a bootloader, but a binary image updater, which should be run by
main code.
digital/io-hub/src/apbirthday: add !b to go to bootloader
digital/ucoolib/ucoolib/utils/crc: add CRC32
digital/ucoolib/build: compute CRC32 when building a .bin
digital/io-hub/src/apbirthday: compute code CRC