Hide "unattached speeches" header unless required.

Also fix unattached speeches styling, and breadcrumb doubling bug.
Merge branch '232-unattached-speeches'
show friendly message on empty section pages
Merge branch '39-add-speech-to-section'
add masonry javascript to section_list.html
hide speaker portraits and railroad lines for unattached speeches
show section in speech editing sidebar, and hide hard-coded speaker suggestions
move "Save speech" button to bottom of speech editing form
make empty "speaker" select2 box match "section" select2 box
Merge ssh://git.mysociety.org/data/git/public/sayit into speech-editing-form
Merge branch 'speech-editing-form' of ssh://git.mysociety.org/data/git/public/sayit into speech-editing-form