Fix temporary for exceptions >= 0.6

As others have posted in the issue tracker, exceptions 0.6 breaks temporary 1.2.0.2 (the most recent on hackage).

As github doesn't seem to have 1.2.0.2, I pulled down the tar.gz file from hackage and overlaid it on the github repo. The only change seems to be the lack of upper bounds on packages. I fixed the `MonadMask` problem, bumped the version to 1.2.0.3, and bumped the min bound on exceptions to 0.6.