add UMD support. fix #787
build reveal.min.js
remove needless condition
Fix small misspelling: Mardown -> Markdown
allow tall slides to spread over pages in pdf export
abide by configured slide width when exporting to pdf
Merge pull request #883 from seanfisk/fix-small-misspelling

fix small misspelling: Mardown -> Markdown
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