Site generalisation while keeping pjf's content intact.

Conflicts:
	_layouts/default.html

Based on 26b77df4bc2db12a431dfbf7f6dfd18cd140bbdd
instructions for initial config
make avatar configurable
OCD tweak of an html element.
Use site.avatar in index.html files

Conflicts:
	personal_example/index.html
	youtube_example/index.html