Update to commit 559a9d9 from git@github.com:x-team/wp-stream.git

Includes the following commit(s):

commit 559a9d95f59e03e0de409fadf2012b03d6d15e7c
Author: Frankie Jarrett <frankie@x-team.com>

    Updating screenshot asset and caption

M	assets/screenshot-2.png
M	readme.md
M	readme.txt


git-svn-id: https://plugins.svn.wordpress.org/stream/trunk@820182 b8457f37-d9ea-0310-8a92-e5e31aec5664