Haddock module attributes specified with old syntax

Several modules specify the Haddock hide attribute, but with the old, pre-Haddock-2 syntax.

Attached is a commit to just blindly swap all the old syntax with the new syntax.

However, I suggest we think a bit about whether or not the modules ought to have been hidden, whether or not they should continue to be hidden, and whether or not anything else should be hidden. If we decide anything other than the obvious, I'm happy to close this pull request and formulate a new one.

See also [this SO question](http://stackoverflow.com/q/13914500/812053) – some of the hide options are on modules which aren't exported, and hence are probably redundant.