Copter: init_rc_out in cli's compassmot setup

Bug fix to allow cli's compass motor compensation to be run from the
mission planner's terminal window
WPNav: initialise desired roll, pitch

bug-fix to resolve 1/10th second twitch when loiter or waypoint
controller are first engaged
AP_Common: make PACKED depend on architecture

this will remove lots of warnings when building with arduino
AP_GPS: use PACKED attribute instead of pragma pack
SITL: use PACKED attribute instead of pragma pack
AP_Param: use PACKED attribute in examples
SITL: use PACKED attribute in fdm structure
Copter: bug fix for RTL yaw control

Nose was only pointing home if your initial altitude was above the
RTL_ALT
HAL_PX4: include visibility.h

needed for new nuttx structure
HAL_PX4: moved rc.APM to new ROMFS directory
PX4: added base ROMFS files from upstream
PX4: added in remaining example mixers
build: added support for the new PX4 build system
build: fixed build_binaries.sh for new PX4 build
PX4: auto-build the archives if needed
build: added px4-archives target
PX4: changed EXTRAFLAGS to EXTRADEFINES for PX4
PX4: need led driver in build for latest upstream changes
PX4: fixed px4io build in build_binaries.sh
build: fixed build_all_px4.sh for new PX4 build