fix all remaining -Wincomplete-uni-patterns warnings

A couple of these were probably actual bugs in edge cases. Most of the
changes I'm fine with. The fact that aeson's object returns sometihng
that we know will be an Object, but the type checker does not know is
kind of annoying.

Config/Cost.hs

@@ -46,9 +46,9 @@ insertCostAfter [] _ = []
 insertCostAfter l pos
 	| pos < 0 = costBetween 0 (l !! 0) : l
 	| nextpos > maxpos = l ++ [1 + l !! maxpos]
-	| item == nextitem =
-		let (_dup:new:l') = insertCostAfter lastsegment 0
-		in firstsegment ++ [costBetween item new, new] ++ l'
+	| item == nextitem = case insertCostAfter lastsegment 0 of
+		(_dup:new:l') -> firstsegment ++ [costBetween item new, new] ++ l'
+		_ -> error "insertCostAfter internal error"
 	| otherwise =
 		firstsegment ++ [costBetween item nextitem ] ++ lastsegment
   where