add Bootstrap!

Now we can incrementally start using bootstrap components in place of
our own.
bootstrap-ize gallery thumbnails
bootstrap-ify footer
switch to sticky top nav bar
more work on bootstrap
dedent some lists (indent was turning into a blockquote)
make content narrower, and put todos, diagrams, etc. in panels.
move blog post stuff etc. to "sightings" page
use callouts for todo and warning, remove yellow fill from warning sign
table of contents is now on the left side

Still need to style it better, make it sticky, and use "affix" to make it
automatically follow the position in the text.
add affix/spy stuff so TOC follows the contents

Kind of clunky and needs better styling.
Stealing css for bootstrap docs.  Should customize it to our own liking.
Side TOC looks a bit nicer.  More styling to do.
nifty auto-collapsing auto-following sidebar TOCs stolen from bootstrap docs!
Merge branch 'master' into bootstrap

Conflicts:
	web/templates/default.html
Merge branch 'master' into bootstrap
add "Haskell, Ising, Markov & Metropolis" to sightings list
added banner
a rough attempt at mouseover scrolling
additions to gallery