Bug 539029: Fix CSS theming in builds

Change-Id: Ifb069be56070ea0be6a1e9b016170dc11a9b4ca5
diff --git a/ltk/org.eclipse.statet.ltk.ui/build.properties b/ltk/org.eclipse.statet.ltk.ui/build.properties
index 06f0c03..d98e128 100644
--- a/ltk/org.eclipse.statet.ltk.ui/build.properties
+++ b/ltk/org.eclipse.statet.ltk.ui/build.properties
@@ -7,6 +7,7 @@
               plugin.properties,\
               .,\
               icons/,\
+              css/,\
               about.html
 src.includes= .settings/org.eclipse.core.resources.prefs,\
               schema/