To remove timestamp, reply, favorite and retweet links add:
.twtr-timestamp { display: none; }
.twtr-reply { display: none; }
.twtr-fav { display: none; }
.twtr-rt { display: none; }
The only annoying thing left is some dots that used to be in between these links.
To remove them you can copy the widget.js script to your own site and remove all occurances of · (or the complete links)