Partial layouts clubbed into a folder.

--HG--
rename : templates/layouts/linked-talk-speaker-single.html => templates/layouts/partials/linked-talk-speaker-single.html
rename : templates/layouts/linked-title-subtitle.html => templates/layouts/partials/linked-title-subtitle.html
rename : templates/layouts/linked-title.html => templates/layouts/partials/linked-title.html
rename : templates/layouts/title-blurb.html => templates/layouts/partials/title-blurb.html
Session list now uses common template + more refactors.