add UMD support. fix #787
build reveal.min.js
revert from flexbox for pdf centering, use js for PDF setup
remove needless condition
allow tall slides to spread over pages in pdf export
abide by configured slide width when exporting to pdf
some more flexibility for pdf export sizes
simplify pdf layout
readme update, kill event listeners when printing pdf
enable reveal.js keyboard shortcuts anywhere in notes window
Merge branch 'feature/print' into dev
fix non-pdf printing (closes #881)
fix transitions in firefox
improvements to print stylesheet
abide by configured width/height when printing to pdf
fix #627
new api method: getBackgroundSlide
break showing/hiding of slides into separate methods
disregard v index when there is no vertical slides/backgrounds in getSlide/getSlideBackground
fix getindices test