remove Utility.Conditional and use IfElse

This drops the >>! and >>? with the nice low fixity. IfElse does have
undocumented >>=>>! and >>=>>? operators, but I deem that too fishy.
Anyway, using whenM and unlessM is easier; I sometimes mixed the operators
up.

Git/Command.hs

@@ -30,8 +30,8 @@ runBool subcommand params repo = assertLocal repo $
 {- Runs git in the specified repo, throwing an error if it fails. -}
 run :: String -> [CommandParam] -> Repo -> IO ()
 run subcommand params repo = assertLocal repo $
-	runBool subcommand params repo
-		>>! error $ "git " ++ show params ++ " failed"
+	unlessM (runBool subcommand params repo) $
+		error $ "git " ++ show params ++ " failed"
 
 {- Runs a git subcommand and returns its output, lazily. 
  -