adding first pass as substep navigation
updated readme, added example
linked to impress.js from README
fixed overload animation to run on present
gold plating README
updating examples and comments
cleaned up substep functions, added events
more gold plating for demo
cleaning up example code
updating with link, fixing styles
improved comments
fix retrieving previous substep

threw an error on the console
Merge pull request #1 from lucas-clemente/patch-1

fix retrieving previous substep
merge with substep