Add some menu icons

ressources.qrc

@@ -28,6 +28,9 @@
         <file alias="keyboard">images/keyboard.png</file>
         <file alias="marker_start">images/marker_start.png</file>
         <file alias="marker_stop">images/marker_stop.png</file>
+        <file alias="undo">images/undo.png</file>
+        <file alias="redo">images/redo.png</file>
+        <file alias="configure">images/configure.png</file>
     </qresource>
     <qresource prefix="/text">
         <file>AUTHORS</file>

src/Gui/ui/MainWindow.ui

@@ -115,6 +115,10 @@
    </property>
   </action>
   <action name="actionPreferences">
+   <property name="icon">
+    <iconset resource="../../../ressources.qrc">
+     <normaloff>:/images/configure</normaloff>:/images/configure</iconset>
+   </property>
    <property name="text">
     <string>Preferences</string>
    </property>
@@ -221,11 +225,19 @@
    </property>
   </action>
   <action name="actionUndo">
+   <property name="icon">
+    <iconset resource="../../../ressources.qrc">
+     <normaloff>:/images/undo</normaloff>:/images/undo</iconset>
+   </property>
    <property name="text">
     <string>Undo</string>
    </property>
   </action>
   <action name="actionRedo">
+   <property name="icon">
+    <iconset resource="../../../ressources.qrc">
+     <normaloff>:/images/redo</normaloff>:/images/redo</iconset>
+   </property>
    <property name="text">
     <string>Redo</string>
    </property>