started converting to use optparse-applicative

This is a work in progress. It compiles and is able to do basic command
dispatch, including git autocorrection, while using optparse-applicative
for the core commandline parsing.

* Many commands are temporarily disabled before conversion.
* Options are not wired in yet.
* cmdnorepo actions don't work yet.

Also, removed the [Command] list, which was only used in one place.

Command/Test.hs

@@ -11,10 +11,10 @@ import Common
 import Command
 import Messages
 
-cmd :: [Command]
-cmd = [ noRepo startIO $ dontCheck repoExists $
+cmd :: Command
+cmd = noRepo startIO $ dontCheck repoExists $
 	command "test" paramNothing seek SectionTesting
-		"run built-in test suite"]
+		"run built-in test suite"
 
 seek :: CommandSeek
 seek = withWords start