bug 452716: add about.html to all plug-ins

Signed-off-by: Florian Thienel <florian@thienel.org>
diff --git a/org.eclipse.vex.core/build.properties b/org.eclipse.vex.core/build.properties
index 819cbe8..1532a5d 100644
--- a/org.eclipse.vex.core/build.properties
+++ b/org.eclipse.vex.core/build.properties
@@ -3,4 +3,6 @@
 bin.includes = plugin.properties,\
                META-INF/,\
                .,\
-               plugin.xml
+               plugin.xml,\
+               about.html
+src.includes = about.html