control law now reflects nav controller's requests
velocity hold: fix axes swap, tune gains down
attitude control: ui sensitivity is now parameterized

and the control loops themselves are just specified by setpoint
and units for setpoints are always radians
gcs: debug is a separate stream
position UI has tunable sensitivity
add Flight.Control.StateDerivativePID, same as StatePID with user provided deriv est
ivory-px4-hw: GPS reports time in Position
hil: add time to Position
Navigation.Velocity: estimate Position acceleration per fresh sample
Merge remote-tracking branch 'origin/master' into pos-hold
hil params: velocity control is working somewhat reasonably
ivory geo gitignore
smaccmpilot: add identical navcommand and navlaw types
smaccm-mavlink: regen with smaccmpilot nav command message
flight: plumb nav_command from gcs to nav, nav_law from nav to gcs
navigation wip
toolchain: use -O0 to get around apm blob bugs
wibble
smaccm-mavlink: regen change to smaccmpilot_nav_cmd
nav command: refactor validity boolean into enable/disable/none