The only part of the friends_timeline API call that was deprecated was the version which requests someone else's timeline. Asking for your own timeline is still perfectly fine. Please can you add this back in?

Deprecated: $request = 'http://twitter.com/statuses/friends_timeline/' . urlencode($id) . '.' . $this->type . $qs;

Still Good: $request = 'http://twitter.com/statuses/friends_timeline.' . $this->type . $qs;

I'm updating the library right now. Will look at this this weekend. Feel free to create a patch and submit back. You'll get props.

This is invalid. The request for friends_timeline is a wrapper around user_timeline with self ID passed.

There's a reason for them being different API methods:

friends_timeline is about showing your friends' updates. user_timeline is for showing one user's updates.