So no need for connect window close test here

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

This allows use of compile time Object::connect syntax

Simple starting point to view testing

This was leftover from a problem I was having with virtual slots

Allows for UI unit tests to be written:
- Ability to respond to expected message boxes
- Ability to fail test if unexpected message boxes occurs

Allows you to run a single unit test from the command line

- allow unit tests to use QGCApplication
- clear global singletons for each unit test run

Destroyed signal must have been working incorrectly in the past.

Centralize all connecting and disconnecting of links through
LinkManager::[Connect|Disconnect]Link api. Connect/Disconnect no longer
allowed through LinkInterface. This allows creation of new
LinkManager::setConnections[Suspended|Allowed] methods to disallow
connections as needed.

This allows you to determine if full parameter list is ready if you
missed the parameterListUpToDate signal.

This allows you to determine if full parameter list is ready if you
missed the parameterListUpToDate signal.