Everything you need to know about the changes coming to Facebook
     Facebook announced a series of features and updates at its annual F8  Developer Conference in San Francisco on Wednesday, and while the news  is mostly targeted for developers and app designers right now, it could  eventually mean big things for Facebook users.   CEO Mark Zuckerberg kicked off the two-day long conference with a  major update to Facebook Messenger, the social network's chatting tool.  Users will be able to send photos, GIFs, music and integrate with apps  like ESPN and the Weather Channel.    See also: You can now do a whole lot more with Facebook Messenger  Other improvements were made to Facebook's video player and its app  analytics platform. The social network announced it's getting into the  Internet of Things trend, too.   In case you missed the presentation, here's a look at everything you need to know:     Facebook Messenger as a hub  Perhaps the biggest update unveiled during Zuckerberg's keynote is  that Facebook Messenger is becoming ...