Lens Next branches setup.
Merge branch 'master' into lens_next

Conflicts:
	project.json
Example for a key reference re-rendered after asynchronous lookup.
Improved asnych external content example.
Merge branch 'master' into lens_next

Conflicts:
	project.json
Generalized Reader.jumpToResource in regard of panels.
Merge branch 'master' into lens_next
Fix regression.
Merge branch 'master' into lens_next

Conflicts:
	src/panel_specification.js
Merge branch 'master' of https://github.com/elifesciences/lens
Merge branch 'master' into lens_next
Experimental implementation and example environment for Related Articles.
Styling related articles panel.
Some more data

In preparation for key-references use-case.
Merge with master
Use related article example.
Merge with latest master.
Merge branch 'master' into lens_next

Conflicts:
	src/lens.js
Merge branch 'master' into lens_next

Conflicts:
	src/lens.js
Remove obsolete data.