Support --metadata field<number, --metadata field>number etc to match ranges of numeric values.

Similarly (well, for free), support preferred content expressions like
metadata=field<number and metadata=field>number

Backend/Hash.hs

@@ -5,7 +5,7 @@
  - Licensed under the GNU GPL version 3 or higher.
  -}
 
-{-# LANGUAGE CPP, BangPatterns #-}
+{-# LANGUAGE CPP #-}
 
 module Backend.Hash (
 	backends,