Update tests/README

Also add `.md` suffix so that github displays it as markdown.

Change-Id: If5a81f753f0729bbf5b666fd674fada8474a3ba5
Fix RT client startup.

Fix `fetch` regression introduced by parameter reordering in
2e756ee2936015960931c5a72811a347a87e3c10.

Fix regression/crash in `ParsoidConfig#setInterwiki` introduced by
819b2cf472be3c9e3540a2d79309f030ee7e1d6c.

Add `err.stack` to console log to ease debugging future crashes of
this sort.

Change-Id: I6d511fe6e4a01feaea094e222e9b236819d2b66e
Merge "Update tests/README"