minimal changes
added post -its for explainer page, adjusted the H1 size for book titles.  Disabled StackScore dropdown.
added buttons and explainer page stuff
edits for kim and david
spelling, notes, etc
in sms logic, changed shelflife reference to stacklife. fixes #83
fixed homepage, about page, explainer page, some font stuff, and arrows at bottom of the search page
Merge branch 'develop' of github.com:harvard-lil/stacklife into develop