add newtypes for QuickCheck to avoid LANG=C issues

All properties changed to use them, except for
prop_encode_c_decode_c_roundtrip, which already filtered to ascii
for other reasons.

A few modules had to be split out, because Setup does not build-depend
on QuickCheck.

Annex.hs

@@ -5,7 +5,7 @@
  - Licensed under the GNU AGPL version 3 or higher.
  -}
 
-{-# LANGUAGE GeneralizedNewtypeDeriving, PackageImports, BangPatterns #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving, BangPatterns #-}
 
 module Annex (
 	Annex,