Changes to support using vimeo albums

Conflicts:
	Gemfile.lock
	_layouts/video.html.slim
Add in standalone videos

Conflicts:
	Gemfile.lock
Upgrading Asciidoctor to 1.5.0
Adding some info that was missing before
Needed change to the DCP

We need to include a new preprocessor for videos now.
DEVELOPER-842 normalise contributors at build time
DEVELOPER-842 temporary upgrade to my aweplug branch