#692 added site url's

Author: jantje

website/WebContent/fragments/how_to/install_V4_plugin.md

@@ -1,11 +1,13 @@
 This page contains Detailed instructions on how to install the Arduino Eclipse plugin version 4.
 ===
 
-If you are not sure what you want to install please see the 
+If you are not sure what you want to install please see the
 [install advice page]("install_advice.shtml").
 
 
 Detailed installation instructions
 -----
- 
+
  Follow the V3 instructions but use the V4 update site
+The stable V4 update site is http://eclipse.baeyens.it/update/V4/stable
+The nightly V4 update site is http://eclipse.baeyens.it/update/V4/nightly