Supersize: Add start_server to run server instead of copying template

Adds a class that wraps SimpleHTTPServer. When start_server is
called, the server starts up and serve files from the template
directory. The data.ndjson file is still created.

Bug: 847599
Change-Id: Id153ae3c8c78b01376d09c53842c747e2b4e04fb
Reviewed-on: https://chromium-review.googlesource.com/1136932
Commit-Queue: Tiger Oakes <tigero@google.com>
Reviewed-by: agrieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576560}
14 files changed