Remove build/ from branch

#91 
After merging this pull request, I would just have to change around some stuff on gh-pages to make it work. Then for production, on your local machine, you just have to `git merge master`, `grunt build`, `git add build/`, etc. The .gitignore file can stay the same because .gitignore only ignores untracked files, and if gh-pages is already tracking the build directory, .gitignore would have no effect on that directory