Losslessly minify default-skin.png
Losslessly minify preloader.gif
Fix autoprefixer not listed in npm dependencies
Add grunt-svgmin
Merge pull request #673 from subzey/assets-minification

Assets minification
Improve keyboard events handling

1. Don't do anything if special key pressed to prevent from overriding
default browser actions.
2. Call preventDefault to avoid conflicts.
build & docs upd
esc handler moved to keydown. Keyup listener removed entirely.
build
docs upd (semantic markup for gallery + schema.org)
docs upd
typo in CSS, closes #679
Merge branch 'master' of https://github.com/dimsemenov/PhotoSwipe