Also removed partially implemented an incorrect getCommunicationStatus
api

Also many LinkManager API changes to further isolate all link
management inside LinkManager.

So this special casing is no longer needed

Plus a large number of other changes to allow for orderly shutdown of
objects without crashes or asserts. This is need for unit tests to
create/delete global state around every test.

This removes confusion as to whether you call UAS::requestParameters
(incorrect) or QGCUASParamManager::requestParameterList (correct) from
client code.

This is the Pixhawk research board, not the PX4 production board.

also adds AMSL output in ft

Fix HIL link reconnect issues due to missing threading flag usage, warn user about missing config and take him to config view if necessary

Fix HIL link reconnect issues due to missing threading flag usage, warn user about missing config and take him to config view if necessary

Most math and backend storage was floats anyways, so most of these changes just half the data copied during function calls without reducing precision.

Enable RC calibration mode during RC calibration to tell vehicle to ignore stick inputs for that period

Altitude splitted to altitudeAMSL and altitudeRelative, speed splitted to airSpeed and groundSpeed. PrimaryFlightDisplay uses airSpeed for FW and groundSpeed for MC.