List paper author somewhere in activity items

[boonebgorges]

Via @sheesh http://commons.gc.cuny.edu/?p=43710

In activity feed, comment items should also list the paper author. Right now it lists the commenter and the paper, but not the paper author.

In other words, the comment action is something like 'Boone left a comment on Foo', saying nothing about who wrote Foo. I would like to avoid having these activity actions get super long (it also adds overhead to the paper loop) but I guess we can make it something like 'Boone left a comment on Foo by Bar'.

This is a low-priority item so I'm not putting it into 1.0 milestone.