Merge / modify entities output

[igorbrigadir]

I may change how the lists of hashtags and mentions are output.

Currenty, the json list is preserved as is. I may change this to output a list like ["@one","@two","@three"] as opposed to preserving the start / end indexes, as these are generally not used.

Dealing with URLs in the same way is possible but i'm not sure how much processing to do on the URLs (show all t.co and unwound urls? or show all? etc.)