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/Fix.hs

@@ -26,7 +26,7 @@ seek :: [CommandSeek]
 seek = [withFilesInGit start]
 
 {- Fixes the symlink to an annexed file. -}
-start :: CommandStartString
+start :: FilePath -> CommandStart
 start file = isAnnexed file $ \(key, _) -> do
 	link <- calcGitLink file key
 	l <- liftIO $ readSymbolicLink file