Oomph: Use master branch for developer installation.

Signed-off-by: Alexander Diewald <diewald@fortiss.org>

oomph/af3.setup

@@ -358,7 +358,7 @@
     </workingSet>
     <description>Standard working set definitions.</description>
   </setupTask>
-  <stream name="test"
+  <stream name="master"
       label="Development">
     <description>Configure the stream / branch of source code.</description>
   </stream>