Topic get recs

topicpanelitem directive passes its list of saved papers to header controller function, which broadcasts down to main controller. The main controller listens for the broadcast, then proceeds to call a new function, abstractsRecFromTopic, which gets recommendations based on the saved papers and updates the view with the recommendations. abstractsRecFromTopic does the same thing as abstractsRec, but it's better to separate the two so we don't assume from which part of the ui the recommendations are requested.