Can't determine join time of a contact

[andrewxhill]

Right now the easiest way is to look for when they first share or message.

Related: #118

Three possible fixes

1. Add the seconds to feed entries (maybe it is hidden in payload. It would also be nice to add contact address to join/leave payload if not there (see ticket above for not knowing)
2. In textile.thread.peers it would be nice to include their join time for that thread in the response.
3. It seems pretty common in chat interfaces that you want to include Join announcements. It might be handy to create a join/leave message type that can be folded into that single textile.messages query

[asutula]

I vote #2. The join item will be in the feed for if/when it needs to be displayed, and having this kind of metadata about thread participants seems to fit perfectly into the response from textile.thread.peers

[asutula]

Also, I can see how having join items in the results of textile.messages, but I think the right solution is to have a single method that lets you get all items from a thread with a filter. So getting all message and joins and leaves would be easy.