added a method that checks similarity between tweets and keeps track of repeated and similar tweets. this is done using the gem similar_tweets
because the new similarity method takes a little longer to long, i've added a loading gif icon to the page. this will show until the results page is loaded.
updated similarity method to igor RTs
removed turbolinks so loading gif still works when user clicks link to return to the homepage and types in another screenname
Merge branch 'similarity_score'