[nav] takeoff detection module

set the launch variable to true based on pitch angle
[ocaml] support display of formatted string in messages

this should close #796
to display an integer (or array of integer) in HEX, just add format="%x" to the field in messages.xml
[modules] separate USE_AIRSPEED_xx flags
[abi] add TEMPERATURE message
[modules] baro modules publish TEMPERATURE via ABI
[modules] ms45xx publishes BARO_DIFF and TEMPERATURE via ABI