US Core Test Kit v0.2.0

• Add US Core v4.0.0 tests.
• Modify reference resolution tests to only check Must Support references.
• Update reference resolution test to store requests.
• Fix string interpolation in reference search checks.
• Fix error message in read tests when id does not match.

US Core Test Kit v0.1.1

• Add .yml files to published gem.

US Core Test Kit v0.1.0

Initial public release.