Fix small misspelling: Mardown -> Markdown
Merge pull request #883 from seanfisk/fix-small-misspelling

fix small misspelling: Mardown -> Markdown
add contribution guidelines from dev
Merge branch 'master' of github.com:hakimel/reveal.js
use node.js 0.10
Use svg instead of png to get better image quality
Merge pull request #1033 from PeterDaveHello/patch-1

ci status indicator is svg instead of png