added distractor task

in distractor.html
Merge pull request #1 from tomkersten/master

Standardized markup & directory structure
Added documentation to rateAudio
Divided experiment into steps; put each step into html file
Redirect fixed, preference has radio buttons

Distractor page now redirects to memory rating page 1 on timeout.
Preference page now has radio buttons
Submit comments expanded
changed speech
fixed slidervals bug