Added benchmark mechanism

Change-Id: Ia49ce229b3812faca178babb0c8ab54afcb349eb
diff --git a/Makefile.PL b/Makefile.PL
index 370a0ae..6d61c3f 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -27,6 +27,7 @@
     'IO::Dir::Recursive' => 0.03,
     'File::Temp'      => 0,
     'Directory::Iterator' => 0,
+    'Dumbbench'       => '0.111',
     'Benchmark'       => 0,
     'Unicode::Normalize' => 0,
     'Carp'            => 0,