YAML Alias and Anchor Support v3

Original PR contains more information on aliases and anchors, see #697.

This update addresses an issue that allows Redmine issue https://redmine.openinfosecfoundation.org/issues/1251 to work.

Buildbot output:
- PR build: https://buildbot.openinfosecfoundation.org/builders/jasonish/builds/3
- PR pcaps: https://buildbot.openinfosecfoundation.org/builders/jasonish-pcap/builds/3