Added parallax scrolling background
Fix: no parallax scrolling in FF

Fixed problem with parallax background  not working under FF
Add option to Gruntfile.js to specify server port
make hiding of address bar configurable
make sure remotes works without notes plugin being loaded #607
Merge branch 'patch-1' of https://github.com/mrshu/reveal.js
add note about port #608
prevent unintended slide change event

This prevents the upcoming slide on the notes page from triggering
slidechanged events.  I believe this fixes issue 578, as well.
update comment
Merge branch 'master' of https://github.com/drhuettl/reveal.js
add contribution guidelines
merge parallax into dev, remove default image #595
update code style to match rest of reveal.js, disable parallax by default #595
move parallax code to separate method #595
update the parallax background when the window resizes #595
use 'url()'-free path when specifying parallax image, refactor so that parallax is applied to background class, remove unused attributes #595
remove extravagant comment
serve remotes js from s3 #611
Focus body when page visibility changes to ensure keyboard shortcuts are usable
Property 'length' is not a variable.