ZTAP-provided default test runner

ZTAP now includes a test runner, which can be linked in path form
directly to the ZTAP step. This is now the preferred way to use ZTAP,
since there's no need to include a separate file in your own program.

This is a feature-only update.

Zig 0.14 compatibility

This release makes ztap compatible with the official 0.14 release of
Zig. No new features are added or planned.

Update panic handler

Zig master changed how default panic handlers are called, this is a tracking update which makes ZTAP compatible with that change.

Master-branch compatible release

This is v0.8.1, modified to build with the latest release of zig master, which have lowercased the names used in Type.

This project will switch to tracking 0.14 when released, in the meantime, if you're using recent builds, this is the release you want.

ZTAG v0.8.1

Unlikely to change in any essential or API way.