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.

Utility/DataUnits.hs

@@ -120,7 +120,7 @@ roughSize units short i
 
 	showUnit x (Unit size abbrev name) = s ++ " " ++ unit
 	  where
-	  	v = (fromInteger x :: Double) / fromInteger size
+		v = (fromInteger x :: Double) / fromInteger size
 		s = showImprecise 2 v
 		unit
 			| short = abbrev