QML JS Inspector: Added method to clear component cache

This one should be called when a component is changed and components
using it need to be reloaded.

src/plugins/qmljsinspector/qmljsdesigndebugclient.h

@@ -76,6 +76,7 @@ public:
     void setObjectIdList(const QList<QDeclarativeDebugObjectReference> &objectRoots);
 
     void setContextPathIndex(int contextPathIndex);
+    void clearComponentCache();
 
 signals:
     void currentObjectsChanged(const QList<int> &debugIds);