explict export lists

Eliminated some dead code. In other cases, exported a currently unused
function, since it was a logical part of the API.

Of course this improves the API documentation. It may also sometimes
let ghc optimize code better, since it can know a function is internal
to a module.

364 modules still to go, according to
git grep -E 'module [A-Za-z.]+ where'

Utility/DottedVersion.hs

@@ -7,7 +7,11 @@
 
 {-# OPTIONS_GHC -fno-warn-tabs #-}
 
-module Utility.DottedVersion where
+module Utility.DottedVersion (
+	DottedVersion,
+	fromDottedVersion,
+	normalize,
+) where
 
 import Common