code clean up on index.html.erb
replaced home video, revised partners & sponsors

The home video used to be the DevCongress-MPower Payments API Hackathon
promo video. It's now the video taken during the event.

I took out BloggingGhana and TechyAfrica from our list of sponsors &
partners
set up controller action and route for eXchange

pages#exchange -> eXchanige is a new thing by DevCongress to bring
programmers at all skill levels to the fireside to have the
all-important chat
Merge branch 'master' into responsive
initial work on /codecamp
initial work on /codecamp
Merge branch 'master' of https://github.com/devcongress/devcongress.com
cleaned up unused routes in the routes file
Merge branch 'master' into responsive