reorganized posix sitl launch scripts, reorganized mavros python test scripts (integration tests) and updated them for posix sitl, removed old and not working integration tests

Signed-off-by: CarlOlsson <carlolsson.co@gmail.com>

How can someone just add a FIXME for such a simple case?!

This fixes the previously introduced unit test. It fixes the case where
orb_subscribe_multi is called multiple times with different instances,
and no publisher advertised the topic yet. In this case all subscribers
got the same instance 0.

This fails both on NuttX & Linux

In the existing implementation, the map had to be searched twice.

This fixes a subtle bug: the instance parameter of orb_advertise is an output
parameter and thus its value can be random. However in node_open this value
is accessed and thus the open(...) call could succeed even though it should
not. This can happen for example if a second advertiser of a topic calls
orb_advertise_multi with *instance=0.

The existing implementation worked only because *instance was initialized
with -1 in most cases.

we are now using the vehicle_landing_detected topic
instead of getting the landed flag from the vehicle status topic

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

Adding new CMake config files which will be used to generate a build which uses the legacy sensor drivers.  This is only temporary until integration with the corresponding PX4 DriverFramework drivers is complete.

sensor_combined

(Ran AStyle)

Disable free-fall detection when threshold is 0

Added free-fall status in vehicle_status topic