vehicle_local_position topic updated, position_estimator_inav and commander fixes, only altitude estimate required for SETBELT now.

Note; only tested with gdb 7.6. Will definitely not work with the stock PX4 toolchain's gdb.

This reverts commit b08ca024.

Flesh out PX4IO documentation comments and delete unnecessary class var

commander, multirotor_att_control, position_estimator_inav: position valid flag fixed, other fixes and cleaunup

Doxygenate and style dsm.c

Replace C++ style comments with C comments

WIP, TODO fixedwing

One file a day... this'll take a while!

Conflicts:
	Documentation/flight_mode_state_machine.odg