…e, use state interface in navigation instead

body_rate_d is computed by the controller now, but it is not divided by
the period yet, so the gain may change for different frequencies.
it was not really computed before anyway... I doubt someone was really
using this.

Only the basic navigation routines are converted to the new state
interface
Some stuff are missing into the state interface: angle of attack and
sideslip angle

FW can fly in simulation using basic navigation routines
Most of the ahrs filters are already feeding the interface, so it should
work as well
The ins_neutral_* are missing for now

Nothing has been tested and a lot of code could be optimized, especially
the ins modules

Conflicts:
	sw/airborne/subsystems/nav.h

state interface is directly filled instead

compiling but not tested

- INS interface build for FW and Rotorcraft on the same basis as AHRS
- For FW, most of the old estimator (vertical kalman filter) as been moved
  to the new ins_float. Some triggers are missing for main_ap, especially
  the baro_event since the Baro interface is not done here.
- Some more integration is needed to remove old estimator.c
- INS modules should follow the general interface
- FW main_ap is not very clear concerning the INS (nor the AHRS) because
  of the freq scaling part from CDW

So we can trigger ins_baro_update.
Start to solve issue #106

need to handle baro measures coming from modules

Some modules can be used directly, some needs some more changes or
adaptation