WizardPage: Add a way to report runtime errors

This will make debugging JSON wizards much simpler!

Change-Id: I03baf4b8d954a9097c0fc4e1180e91d2afe5cc4e
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

src/libs/utils/wizardpage.h

@@ -52,6 +52,10 @@ public:
     void registerFieldWithName(const QString &name, QWidget *widget,
                                const char *property = 0, const char *changedSignal = 0);
 
+signals:
+    // Emitted when there is something that the developer using this page should be aware of.
+    void reportError(const QString &errorMessage);
+
 private:
     QSet<QString> m_toRegister;
 };