Update index.html

Hi! I've corrected some punctuation errors, fixed some typos and translated the "Contact us" paragraph. I think it gives more credibility if it doesn't have any grammar or punctuation issues :)
I also capitalized the Spanish equivalent of "Net Neutrality".
BTW, my mother tongue is Spanish (from Spain, not American Spanish).
I've made a github account just for this, so at least have a look at the modifications! :)
See you!
Merge pull request #31 from sunne/patch-1

Update index.html