Add comparison rule, tolerance if applicable, and hex64 view to test failure text output

[bob80905]

This PR implements some extra quality of life to address confusion in seemingly identical actual and expected results.
Fixes #289

Here's some sample output of what I see when I force a test to fail, changing the expected value from 1 to 21:

[spall]

It might be better to use the c++ hex float format when printing float values since I don't think the standard hex values will be properly interpreted if included in a test file.