Always show seed for failing property check

[ryanpbrewster]

This copies the current behavior of propertyWithSeed(..., None) into property(...)

[ryanpbrewster]

I believe this will address #400

[SethTisue]

rebase?

[ryanpbrewster]

done

[SethTisue]

is someone knowledgeable enough to review this?

[ashawley]

It looks good to me, but @non is the seed expert.

[ryanpbrewster]

Note for reviewer: this is basically copy-pasting the implementation from L111, the PropertyWithSeedSpecifier class. This class will always show the seed for a failing test case.

((Effectively the only change here is adding a call to .viewSeed(fullName) to the end of Prop.delay(p). Let me know if there's anything else I can add here.))

[SethTisue]

perhaps add a test that illustrates the purpose of the change...?