Fix failed connect

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

showLabel was connected to signal but not set as a slot
Fix failed connection

MainWindow::loadDataView has been commented out for 9 months now.
Removed commented out code instead of leaving cruft in.
Commented out uneeded debugging output
Silence some queued signal warnings
QSerialPort emitting constant errors on Unix environment

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.
Missing const
Moved qRegisterMetaType calls to main

Also commented out noisy serial link error output
Remove qDebug statements
Readme Update
Merge pull request #573 from DonLakeFlyer/ReadMe

Readme Update
Merge pull request #567 from DonLakeFlyer/QSerialPortFix

QSerialPort emitting stream of errors
Merge pull request #566 from DonLakeFlyer/MoreConnect

More failed QObject::connect calls
Don't use native menu bar on Linux

Fixes Issue #542
Merge pull request #578 from DonLakeFlyer/UbuntuMenu

Don't use native menu bar on Linux
Merge remote-tracking branch 'upstream/master' into archlinux_dev3
mapripper: use tr() for messagebox text
mapripper: use tr() for messagebox text
Merge branch 'mapripper' into archlinux_dev3
Merge pull request #576 from thomasgubler/mapripper

mapripper: autocontinue to next zoom level after 3s