Wizards: allows filtering of wizards based on Qt version

Every wizard now implements requiredFeatures() to define a feature set.
If the feature set is not satisfied by the available Qt Versions,
the wizard is not shown in the create file/project dialog.

Every Qt version can define the provided feature set in availableFeatures()
defined in BaseQtVersion.

Change-Id: Ie9e2c210d19187b2296451948c36d274f2096623
Reviewed-by: Daniel Teske <daniel.teske@nokia.com>
Reviewed-by: Alessandro Portale <alessandro.portale@nokia.com>

src/plugins/qt4projectmanager/customwidgetwizard/customwidgetwizard.cpp

@@ -38,6 +38,8 @@
 
 #include <projectexplorer/projectexplorerconstants.h>
 
+#include <qtsupport/qtsupportconstants.h>
+
 #include <QtGui/QIcon>
 
 namespace Qt4ProjectManager {
@@ -53,6 +55,11 @@ CustomWidgetWizard::CustomWidgetWizard() :
 {
 }
 
+Core::FeatureSet CustomWidgetWizard::requiredFeatures() const
+{
+    return Core::Feature(QtSupport::Constants::FEATURE_QWIDGETS);
+}
+
 QWizard *CustomWidgetWizard::createWizardDialog(QWidget *parent,
                                                 const QString &defaultPath,
                                                 const WizardPageList &extensionPages) const