Steve asked me to remove this, since the tictactoe game was always
intended as a proof of concept. Now that we have poll and todo
widgets, the sample code for tictactoe has much less value.
We replace the content and type in test_widgets.py to maintain
coverage.
Delete trailing newlines from all files, except
tools/ci/success-http-headers.txt and tools/setup/dev-motd, where they
are significant, and static/third, where we want to stay close to
upstream.
Signed-off-by: Anders Kaseorg <anders@zulipchat.com>