This signal passes the parameter type as well as param info

Removed "Clear Text" context menu from roll down dialog
Fixed "Clear Text" context menu in Info Dialog (renamed to "Clear Messages" in the process)

Shrunk the Message drop down dialog a bit.
Made the Message drop down dialog slightly transparent.

Moving methods from MainWindow to QGCApplication so that more things
can run without a window. Helpful for testing.

Emitting signal beforehand can lead to subtle bugs where code expects
value to be updated and it is not.

UASWaypointManager: don't clear systemid and compid of last partner so that we can still get DO_JUMP updates

UASWaypointManager: accept single waypoint messages in order to update the remaining DO_JUMP repetitions

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.

Also added/converted some logging to debug the problem caused by the
two parameter request apis.

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

This makes unit test output easier to read

This allows use of compile time Object::connect syntax

This makes unit test output easier to read

This function is called automatically when a QSettings object is destroyed,
so is rarely needed to be called explicitly.

There are still some cases where
a QSettings object is passed-by-reference, so there I left the sync() calls as
it's unclear how permanent those objects are and if they'd call sync() before
application shutdown

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

Subclass of QMessageBox which re-implements the static public
functions. There are two reasons for this:
1) The QMessageBox implementation on OSX does now show the title
string. This leads to message boxes which don't make much sense. So on
OSX we set title to text and text to informative text.
2) If parent is NULL, we set parent to MainWindow::instance. This
prevents message boxes which can go behind MainWindow

Do not dynamic cast or de-reference QObject, since object is either in
destructor or may have already been destroyed.

Destroyed signal must have been working incorrectly in the past.