specs: add some pending emit examples.

* specs/ext_yaml_emitter_spec.yaml (emitting): Add some pending
emit examples.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
slingshot: sync with upstream for travis configure warning bug.

* slingshot: Sync with upstream.
* bootstrap.conf (require_bootstrap_uptodate): Remove.  Slingshot
bootstrap now handles out of date bootstrap scripts properly.
(slingshot_files): Remove slingshot.m4.
* configure.ac (SPECL_MIN): Remove.
(SS_CONFIG_TRAVIS): Remove. Move extra rocks from here...
* bootstrap.conf (travis_extra_rocks): ...to here.
* bootstrap: Regenerate.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>