Update version to 0.2.4.

Include loop_call_soon_ and loop_create_future_ in GC traversal.

Fix test dependencies.

Update version to 0.1.9.

Update version to 0.1.8.

Update version to 0.1.7.

Update version to 0.1.4.

Fix readme version.

Update version to 0.1.1.

Update version to 0.1.0.