Update release notes for version 0.5.5 (unreleased)

This will be released soon, hopefully after #1 is resolved and we have
XML formatting for Jenkins runs. I'm frontloading the work here to make
releasing said version easier.

Change-Id: I3d46ff87a337ce31584d4427f19f8c6c9a534a01
Reviewed-on: https://gerrit.causes.com/19255
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Aiden Scandella <aiden@causes.com>
Update readme to suggest simpler directory-scanning mode

Saving them bytes.

Change-Id: Ia6e70c0e98637193188849544bbe19533b477b71
Reviewed-on: https://gerrit.causes.com/19256
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Aiden Scandella <aiden@causes.com>