Fixes bad NaN applied to style on updateParallax.

The previous criteria "verticalSlideCount > 0" would result
in verticalOffset being NaN when verticalSlideCount == 1.

This would cause dom.background.style.backgroundPosition to
be set to something like "123px NaNpx", ultimately preventing
the parallax effect to play (silently failing so far).
define basic black/white colors in the default, non-themed, styles
update (c) year
avoid creating duplicate auto-slide controls #770
remove all use of :not(.image)
drop -o-transition and -ms-transition
server side notes plugin now supports input via data-notes attribute
renamed markdown attributes for clarity and consistency: data-vertical -> data-separator-vertical, data-notes -> data-separator-notes
Merge branch 'master' of https://github.com/ccortezia/reveal.js into dev
don't reduce line height for all headings in base theme (#753)
Merge remote-tracking branch 'remotes/hakimel-original/dev' into hakim-dev

Conflicts:
	Gruntfile.js
	README.md
	css/reveal.css
	css/theme/default.css
	index.html
	js/reveal.js
	js/reveal.min.js
	plugin/markdown/markdown.js
	plugin/notes-server/client.js
	plugin/notes/notes.js
	test/test-markdown-element-attributes.html
	test/test-markdown-slide-attributes.html
	test/test-markdown.html
regenerated CSS files
fixed 404 error in test & example which did not point at the correct path for the Markdown lib code
whitespace police raid
preliminary Jolicode theme update from Damien Alexandre
change version to 2.7.0 (dev)
fix pdf print bug in chrome 33 #808
Merge branch 'master' of github.com:hakimel/reveal.js into dev
add get/setState methods for persisting and restoring presentation state
minimal reorganization of the lib/ directory: moved highlight.js CSS styles to subdir so that when other libs also deliver CSS files, they can sit in other subdirs, all nicely together in lib/css/