Code is split into different methods for each type of test.
It is also mostly relocated to a new class prism.ResultTesting,
since it should not really be tied to the Property object.
The result for testing can now be passed as a Result object,
as well as Double, Integer, etc., with the former being preferred.
This will allow info attached to the Result object to be used
for the correctness, notably accuracy/error info.
Also add a new testing regression test - just some constants,
including border cases - infinity, NaN, etc.
Dave Parker