Fix #79: Autoload ASDF in REQUIRE

When `REQUIRE` is called, autoload ASDF if it hasn't already been
loaded.  User's no longer have to load asdf explicitly anymore.

Update release notes.
3 jobs for rtoy-issue-79-autoload-asdf in 17 minutes and 8 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #2763
linux
linux-runner

00:07:36

passed #2773
osx
osx-runner

00:09:31

failed #2764
osx
osx-runner