And fix a couple things. We should now be able to fetch content
from the production server.

- Set app_type back to TEST_APP
- I've replaced the old test feed query response with a new one
  from the new server. I've hand-edited the response to remove
  content that might be copyrighted, but it's unchanged other
  than that.
- Use our proto-printers to simplify the
  stream_model_update_request_unittest
- Add more .sh scripts to translate protos, making them all
  pipe stdin/stdout.

Bug: 1044139
Change-Id: Ib0053471ff732b3f4d6fe6ef653c17c41769ce62
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2154811Reviewed-by: Ian Wells <iwells@chromium.org>
Commit-Queue: Dan H <harringtond@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762066}