Don't use native menu bar on Linux

Fixes Issue #542

More failed QObject::connect calls

QSerialPort emitting stream of errors

Readme Update

Fix distance to next waypoint widget in QuickView.

This patch fixes a bug that display 0 for distances to waypoint more
than 10km.

Besides that, it also homogenize the naming of the label to
"distToWaypoint" instead of "distToWP". Old configuration files (in
home directory), should be hacked or removed in order to see this
change.

Signed-off-by: Paul Chavent <paul.chavent@onera.fr>

Flightgear HIL: remove disable-intro-music argument 

Also commented out noisy serial link error output

Reverting previous Installer commit

Figured out why command line builds were not working. To build Windows
release from command line you need msbuild …
/property:Configuration=Release

This fix was pulled across from current QSerialPort codebase. I looked
into pulling across newer version of full QSerialPort. While doing that
I discovered that the version we are using has already been hacked to
work with us. It was fairly involved to redo those hacks. So decided to
pull individual change across instead since our version is already not
clean. When we switch to Qt5 all this will go away.

Changes to allow msbuild to build installers

MainWindow::loadDataView has been commented out for 9 months now.
Removed commented out code instead of leaving cruft in.

showLabel was connected to signal but not set as a slot

There is no such things as a clicked signal on QWidget. You activate
new UAS from right-click menu.

Failed QObject::Connect fix

ui->waitingLabel is deleted and set to NULL when mode is PX4. Must
check for NULL before using it.

The connect call was generating debug output to identify that it was
failing. After looking at the code realized that this connect is not
needed. The group box is removed when UASListWidget::removeUAS method
is called.

Second change in the file fixes a crashing bug when the last UAS is
removed. Need to exit the iterator after we modify it.

Issue 535 fix

Google earth: Corrected #ifdef for Google Earth-specific code.

Radio Calibration: Turning on/off advanced config show WIP plane view

3dviews

Disable text output from GAudioOutput.

All it does is clutter the terminal and it's not doing anything anyways.

No idea why, but manipulating CONFIG inside the build file confuses
msbuild command line builds. Work fine if you build from the IDE!

fix unused-but-set-variable warnings/errors in map3D