Today I had to change the implementation of the Annex monad. The old one
turned out to be buggy around exception handling -- changes to state
recorded by code that ran in an exception handler were discarded when it
threw an exception. Changed from a StateT monad to a ReaderT with
a MVar. Really deep-level change, but it went off without a
hitch!

Other than that it was a bug catch up day. Almost entirely caught up once
more.
