Fix build.
startTask[WithInVar] should always produce an ST (C ()) a b computation.
Better representation of queues.
Get rid of NameT crap in TaskGenMonad.
Turn TaskGen monad into a newtype, for less annoying error messages.
Get rid of TODO which was fulfilled by the new queue representation.
Introduce SyncInfo type, making synchronization code explicit.
Clean up TaskGen{Monad,Types} slightly.
Better version of the sync code.

Sync is now handled by tacking Sync statements onto the end of
computers, and by inserting knowledge about whether to propagate
termination to upstream/downstream queues into read/write code
for internal queues.
Fix(?) queue close syncing in pars.