sim file parser and generator

The generator doesn't emit the best possible connect commands,
but it does output something valid. Eg, an input like:

connect A <-> B <-> C <-> D

becomes:

connect A <-> B <-> C
connect C <-> D

Also:

connect A -> B <- C

becomes:

connect A -> B
connect C -> B

Which could be improved.

Also disconnect commands are not prettified at all, but probably there's
no reason to.

Command/Sim.hs

@@ -29,7 +29,6 @@ seek _ = do
 		let getpath = GetSimRepoPath $ \u -> tmpdir </> fromUUID u
 		let st = emptySimState rng repobyname getpath
 		st' <- runSimCommand (CommandInit (RepoName "foo")) st
-			>>= runSimCommand (CommandTrustLevel (RepoName "foo") "trusted")
 			>>= runSimCommand (CommandUse (RepoName "bar") "here")
 			>>= runSimCommand (CommandConnect (RepoName "foo") (RemoteName "bar"))
 			>>= runSimCommand (CommandConnect (RepoName "bar") (RemoteName "foo"))