Updating docblock with explanation of why it's good to sort UUIDs
Return null for the version if variant isn't RFC 4122
Allow a 128-bit integer formatted as a hex string in Uuid::fromString()
Add some code comments to explain the time value being used.
Enhance tests for version-3 and version-5 UUIDs with more known values
Enhance the massive time test with more usec values and compare times
Enhance tests by using an array of known values from the Python UUID tests