Added that requests with JavaScript as the priority mime type in the accept header and no format extension in the parameters will be treated as though their format was :js when it comes to determining which template to render. This makes it possible for JS requests to automatically render action.js.rjs files without an explicit respond_to block  [DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8956 5ecf4fe2-1ee6-0310-87b1-e25e094e27de