Comment out some dead code found with -fwarn-unused-binds

Also fixed some warnings and tightened some imports

src/compiler/GF/Compile/PGFtoHaskell.hs

@@ -273,13 +273,13 @@ hSkeleton gr =
    valtyps (_, (_,x)) (_, (_,y)) = compare x y
    valtypg (_, (_,x)) (_, (_,y)) = x == y
    jty (f,(ty,_,_,_)) = (f,catSkeleton ty)
-
+{-
 updateSkeleton :: OIdent -> HSkeleton -> (OIdent, [OIdent]) -> HSkeleton
 updateSkeleton cat skel rule =
  case skel of
    (cat0,rules):rr | cat0 == cat -> (cat0, rule:rules) : rr
    (cat0,rules):rr               -> (cat0, rules) : updateSkeleton cat rr rule
-
+-}
 isListCat :: (OIdent, [(OIdent, [OIdent])]) -> Bool
 isListCat (cat,rules) = "List" `isPrefixOf` cat && length rules == 2
 		    && ("Base"++c) `elem` fs && ("Cons"++c) `elem` fs
@@ -289,13 +289,13 @@ isListCat (cat,rules) = "List" `isPrefixOf` cat && length rules == 2
 -- | Gets the element category of a list category.
 elemCat :: OIdent -> OIdent
 elemCat = drop 4
-
+{-
 isBaseFun :: OIdent -> Bool
 isBaseFun f = "Base" `isPrefixOf` f
 
 isConsFun :: OIdent -> Bool
 isConsFun f = "Cons" `isPrefixOf` f
-
+-}
 baseSize :: (OIdent, [(OIdent, [OIdent])]) -> Int
 baseSize (_,rules) = length bs
     where Just (_,bs) = find (("Base" `isPrefixOf`) . fst) rules