Add 'empty text' to all the version selection dialogs.

Customize it for the Forge one so people finally shut up about 1.7.4

gui/dialogs/VersionSelectDialog.ui

@@ -15,7 +15,7 @@
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>
-    <widget class="QTreeView" name="listView">
+    <widget class="VersionListView" name="listView">
      <property name="horizontalScrollBarPolicy">
       <enum>Qt::ScrollBarAlwaysOff</enum>
      </property>
@@ -65,6 +65,13 @@
    </item>
   </layout>
  </widget>
+ <customwidgets>
+  <customwidget>
+   <class>VersionListView</class>
+   <extends>QTreeView</extends>
+   <header>gui/widgets/VersionListView.h</header>
+  </customwidget>
+ </customwidgets>
  <resources/>
  <connections>
   <connection>