fix some mixed space+tab indentation

This fixes all instances of " \t" in the code base. Most common case
seems to be after a "where" line; probably vim copied the two space layout
of that line.

Done as a background task while listening to episode 2 of the Type Theory
podcast.

Remote/Web.hs

@@ -120,7 +120,7 @@ checkKey' key us = firsthit us (Right False) $ \u -> do
 			Url.withUrlOptions $ catchMsgIO .
 				Url.checkBoth u' (keySize key)
   where
-  	firsthit [] miss _ = return miss
+	firsthit [] miss _ = return miss
 	firsthit (u:rest) _ a = do
 		r <- a u
 		case r of