Makes twttr global variable play nice if it's already loaded.
Makes twttr global variable play nice if it's already loaded.

* The new snippet checks for the existence of window.twtrr before creating
it. Before this change, if your application happened to load Twitter's
[conversion tracking script](https://platform.twitter.com/oct.js), an
error would be thrown because that script doesn't define twttr.ready
which is a function this addon relies on.

gordonbisnor/ember-social,plyfe/ember-social,jpadilla/ember-social,plyfe/ember-social,danmcclain/ember-social,chrislopresto/ember-social,danmcclain/ember-social,jpadilla/ember-social,chrislopresto/ember-social,gordonbisnor/ember-social