389: Add category to update site

* Enable nightly

Author: wimjongman

it.baeyens.arduino.product/arduino.product

@@ -357,7 +357,7 @@ rights to a jury trial in any resulting litigation.</p>
    <repositories>
       <repository location="http://download.eclipse.org/releases/mars" enabled="true" />
       <repository location="http://download.eclipse.org/eclipse/updates/4.5" enabled="true" />
-      <repository location="http://eclipse.baeyens.it/nightly" enabled="false" />
+      <repository location="http://eclipse.baeyens.it/nightly" enabled="true" />
       <repository location="http://eclipse.baeyens.it/V3" enabled="true" />
    </repositories>