publish: added tests for expand_in_reply_to urls

Added unit tests to cover the functionality of expand_in_reply_to.
Tries a variety of post types, with syndication urls represented
a few different ways.

expand_in_reply_to_tests
 1. ✓ simple u-syndication(s)
 2. ✓ simple rel-syndication(s)
 3. ✓ p-syndication h-cite
 4. ✓ primary h-entry is inside an h-feed
 5. ✓ failure to fetch inReplyTo url
 6. ✓ inReplyTo url has no microformats
 7. ✓ inReplyTo silo should not fetch anything
healthy mix of verb and target