Synchronize the client with the debug service

The v8 engine is blocked till the client is connected to the service to ensure proper hitting of breakpoints.

Task-number: QTCREATORBUG-5412

Change-Id: Iec772cb547a31fef4cccbd4bb1116699c52d20e5
Reviewed-on: http://codereview.qt.nokia.com/3308
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Kai Koehne <kai.koehne@nokia.com>

src/plugins/debugger/qml/qscriptdebuggerclient.h

@@ -51,6 +51,9 @@ public:
     QScriptDebuggerClient(QmlJsDebugClient::QDeclarativeDebugConnection *client);
     ~QScriptDebuggerClient();
 
+    void connect();
+    void disconnect();
+
     void executeStep();
     void executeStepOut();
     void executeNext();
@@ -58,7 +61,6 @@ public:
 
     void continueInferior();
     void interruptInferior();
-    void shutdownInferior();
 
     void activateFrame(int index);