Added QuickCheck property to Interval

[uwaces]

This commit includes only one very basic property for intervals
at the time of the commit the property successfully runs for 100
instances.

[ChrisEPhifer]

Looks good to me! One place where there were (I think) redundant parentheses.

Also, we shouldn't merge this into master just yet; should hit develop, first, and only merge develop into master once we have something resembling a release.

Not sure if there's an easy way to update a PR to change the target branch, though...

EDIT: Just discovered that it's in fact very easy to change the merge target in a PR, and did so :) So disregard that part of this comment.

[uwaces]

@ChrisEPhifer
I'm happy for this to be merged if you'd like, or we can wait for your modifications to Interval to be on develop, integrate the changes and then merge.

I think the integration work is boils down to changing the Arbitrary instance for Interval, just using the smart constructor you are creating (I left a TODO which should mean all that is required is un-commenting the code in the TODO).

Should this be merged? Or do you want to wait.

[ChrisEPhifer]

@ChrisEPhifer
I'm happy for this to be merged if you'd like, or we can wait for your modifications to Interval to be on develop, integrate the changes and then merge.

I think the integration work is boils down to changing the Arbitrary instance for Interval, just using the smart constructor you are creating (I left a TODO which should mean all that is required is un-commenting the code in the TODO).

Should this be merged? Or do you want to wait.

I think this should wait until #18 is merged, since if we don't wait it will just turn into another PR for the same work.

[ChrisEPhifer]

@uwaces , #18 is now merged into develop, if you want to merge that into your quickcheck stuff and adapt to the new type of intervalFrom.