Add a partial order reduction model option.

This also enables assertions to have multiple options, and allows
property check assertions to have multiple options.
Add a failure watchdog external function.
Update the builtin parser.
Merge pull request #6 from tomgr/feature/partial-order-reduction

Add partial order reduction parsing support
Update package versions.
Inline a copy of Data.Graph.Wrapper.

This has not had its dependencies updated yet.
Update to use hashWithSalt rather than hash.
Update tests for new package versions.
Fix a bug exposed by GHC 7.8.
Fix another potential bug.
Merge pull request #7 from tomgr/feature/updated-deps

Update dependencies for GHC 7.8
Fix test printing under windows.