Added new images folder for tip images and new tip from Alister Hood which demonstrates how to add a tip with an image. Note the use of alias in the qrc file.

git-svn-id: http://svn.osgeo.org/qgis/trunk@15307 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: timlinux

images/images.qrc

@@ -401,4 +401,7 @@
     <file>themes/newgis/mIconPolygonLayer.png</file>
     <file>themes/newgis/mIconTableLayer.png</file>
   </qresource>
+  <qresource prefix="/images/tips" >
+    <file alias="symbol_levels.png">qgis_tips/symbol_levels.png</file>
+  </qresource>
 </RCC>

images/qgis_tips/symbol_levels.png

@@ -162,6 +162,15 @@ QgsTipFactory::QgsTipFactory() : QObject()
                         " it on again when you are ready to have the map draw itself again!"
                       ) );
   addGuiTip( myTip );
+  // Tip contributed by Alister Hood
+  myTip.setTitle(tr("Join intersected polylines when rendering"));
+  myTip.setContent(tr("When applying layered styles to a polyline layer, you can join"
+                      " intersecting lines together simply by enabling symbol levels."
+                      " The image below shows a before (left) and after (right) view of"
+                      " an intersection when symbol levels are enabled.") +
+                      QString("<p><img src=\":/images/tips/symbol_levels.png\"/></p>")
+        );
+  addGuiTip(myTip);
   /* Template for adding more tips
   myTip.setTitle(tr(""));
   myTip.setContent(tr(""