Synchronize common build file.  Put back building of .NET 4.0 assemblies that was removed.
diff --git a/nant-common.xml b/nant-common.xml
index bf7a6ae..568f4d3 100644
--- a/nant-common.xml
+++ b/nant-common.xml
@@ -468,6 +468,7 @@
                 <exec program="nunit-console" failonerror="true" workingdir="build/${current.build.framework}/${current.build.config}">

                     <arg value="${NUnit.Projectfile}" />

                     <arg value="-labels" />

+                    <arg value="-exclude=Manual" />

                     <arg value="-xml=Nunit.TestOutput.xml" />

                 </exec>

             </if>