QML Debugger refactoring

Now, QmlEngine creates the connection to the inferior (debuggee), and
notifies QmlInspector when a connection is established. Before,
inspector created the debugger engin, which was wrong.

QmlEngine's responsibilities are connecting to the debuggee and basic
QML/JS debugging features like locals & watchers, breakpoints etc.
QmlInspector takes care of Live Preview and other fancy inspection
features.

Reviewed-by: hjk

src/plugins/debugger/debuggerengine.h

@@ -76,6 +76,10 @@ public:
     bool breakAtMain;
     QString crashParameter; // for AttachCrashedExternal
 
+    // for qml debugging
+    QString qmlServerAddress;
+    quint16 qmlServerPort;
+
     // for remote debugging
     QString remoteChannel;
     QString remoteArchitecture;