Latest qt renamed qml executable back to qmlviewer, and also named
the executable again QML Viewer instead of Runtime/Launcher.

The run configuration id changed, leaving restored qmlproject without
any run configuration.

Reviewed-by: kkoehne

- It's QML, not Qml. But this is only the file format.
- The umbrella term is Quick (or Qt Quick, to be sorted out)

Putting every class in it's own files + avoid "using namespace"

Since the target names are translated, we cannot use the saved
display name from the user file.

Reviewed-by: Tobias Hunger

 * Ease cross device development by introducing 'targets' which
   group build- and runsettings that are valid for this one target

 Most of the kudos for the code review go to dt. Con, thorbjorn,
 ckandler and others did also review parts of this patch.

Reviewed-by: dt