describe Meteor.AppCache.config.addPath in README
add option to deny AppCache access at runtime

if Meteor.AppCache.config.disableRequest is a function, ask it for every
request if the AppCache manifest should be served. If not return 404.
port code in README from coffeescript to js
describe Meteor.AppCache.config.disableRequest in README
typo
Merge pull request #4 from patte/master

option to deny requests