2.6.0

Major changes:

• Parallax backgrounds (more info, example, thanks @michalsmolinski)
• Added UI for controlling auto slide playback. Appears in the bottom left and includes a visual indicator for when the slide is about to change (more info, example)
• Added support for displaying the current page number (more info, thanks @urielha)
• All configuration values can now be overridden through query parameters, for example: http://lab.hakim.se/reveal-js/?autoSlide=3000&controls=false&loop=true

Other changes:

• Unit tests are now available with ever increasing coverage, run via grunt test
• Fixed vertical slide related bug where isLastSlide() incorrectly returned false
• Updated highlight.js build to include all supported languages
• Fixed bug where smart links (like .navigate-right) did not work when controls were disabled
• Updated grunt and node dependencies to current versions
• Fixed perspective of vertical slide transition in IE10
• The grunt serve task now accepts a port number, for example: grunt server 8181
• Added contribution guidelines
• Fixed issue where keyboard controls did not work after clicking on an external link inside of a presentation and then coming back
• Added support for SVG background images
• Overview mode and progress bar are now disabled in the notes window slide previews
• Added support for per-slide vertical centering, simply add a .center class to the <section>
• If an iframe is embedded inside of a slide it will now receive two postMessages: slide:start when the slide is shown and slide:stop when it is hidden (more info)
• Videos are no longer auto-played in the note window previews
• The data-autoslide of a slide stack is now inherited by its vertical children
• Disabled background transitions between consecutive identical data-backgrounds to avoid flicker
• Added convex, concave and zoom background transitions
• Refactored fragment implementation to fix multiple bugs (see #721)
• Adjusted background transition speed to match slide transitions
• When there is embedded media with data-autoplay set and auto-sliding is on, the auto-slide duration is increased to the duration of the media

Markdown plugin:

• Added support for element attributes (more info, thanks @VonC)
• Added support for slide attributes (more info, thanks @VonC)
• Fixed bug where notes in last Markdown slide were not picked up
• If RevealMarkdown.initialize() is called multiple times it won't repeatedly try to parse the same content