Feature io

I used Rachel's better wording for the first paragraph. I also updated a link on the main page to point to 'io' instead of 'io.html'.

After this pull request is accepted into dev, it needs to be **merged into master**, and pushed to production.

Also, **the address [upe.cs.rpi.edu/io](http://upe.cs.rpi.edu/io) needs to work**, because that's what's printed on the posters, which I am hanging up after Noon on Feb 14th.