Update branch projects to use NUnit 2.5.8.
diff --git a/nant.build b/nant.build
index a089933..23dfa6a 100644
--- a/nant.build
+++ b/nant.build
@@ -61,7 +61,7 @@
 		<!-- Property grouping for 'vendor.nunit.org' -->
 		<property name="vendor.nunit.org.name" value="NUnit" />
 		<property name="vendor.nunit.org.group" value="org.nunit" />
-		<property name="vendor.nunit.org.version" value="2.5.5" />
+		<property name="vendor.nunit.org.version" value="2.5.8" />
 		<property name="vendor.nunit.org.filenames" value="nunit.framework.dll" />
 
 		<!-- Property grouping for 'vendor.tibco.org' -->