remove command type definitions

These were a mistake, they make the type signatures harder to read and
less flexible. The CommandSeek, CommandStart, CommandPerform, and
CommandCleanup types were a good idea, but composing them with the
parameters expected is going too far.

Command/Untrust.hs

@@ -20,7 +20,7 @@ command = [repoCommand "untrust" (paramRepeating paramRemote) seek
 seek :: [CommandSeek]
 seek = [withWords start]
 
-start :: CommandStartWords
+start :: [String] -> CommandStart
 start ws = do
 	let name = unwords ws
 	showStart "untrust" name