change excelsior is
better challenge
challenge changes
challenge accepted?
optimize pngs
added the intended humor to whimsy
padding on interrupt
wording changes
Alt tags and tweaks

@esteinborn I fixed a typo on one of your slides, line 458, just a
heads up so there's no merge conflict
White bg on speaker notes print
updated title
Grid demo content
Merge pull request #113 from esteinborn/grids

Grid demo content, closes #112
Merge pull request #114 from esteinborn/master

Master to gh-pages