Fixed forms link in README.md

Currently, "look like this" link for form inputs is http://twitter.github.com/bootstrap/#forms. This link appears to be outdated because it sends you to the top of http://twitter.github.com/bootstrap and does not contain information about forms. The new link, http://twitter.github.io/bootstrap/base-css.html#forms, corrects this problem by sending you to the forms section.
Merge pull request #4 from KevinPike/master

Update forms link in README.md