tweet-info-page: Unify name/screen_name look with profile page
ProfilePage: Don't load so many tweets

35 is a little bit much.
UserStream: Add BLOCK and UNFOLLOW events
FilterPage: Also show the blocked users
UserStream: Add EVENT_UNBLOCK event
ProfilePage: Set the block_menu_item's status on_join

Since we are already doing a call to 1.1/friendships/show.json,
we can simply use that information.
FilterPage: Add new blocked user via an event

Using the UserStream's new EVENT_BLOCK.
filter-page: Show user filter explanation
ProfilePage: Don't block a user if they are already blocked

This happened because the GtkCheckMenuItem's toggled signal was called
when we set the item's state in load_friendship.
ProfilePage: Set the follow button state on blocking

This is important since blocking a user the authenticating user is
following means unfollowing them.
ProfilePage: Set the block item's state when following

If the authenticating user blocks this user and then follows him, he
implicitly unblocks him.
FilterPage: Also remove users via EVENT_UNBLOCK
filter-page: Initially hide user_label and user_list
FilterPage: Only show the user_list if it isn't empty