build.sh: Bump DATE to 20160804
build.sh: Bump DATE to 20160804

Get a Tornado >4.1.0 for working SNI in Thumbor [1,2,3,4].

[1]: https://tools.ietf.org/html/rfc6066#section-3
[2]: https://github.com/thumbor/thumbor/issues/409
[3]: https://github.com/tornadoweb/tornado/pull/1270
[4]: https://github.com/tornadoweb/tornado/commit/ab706d692e83d146b2b8ecfc502414bc49cbdd01

fr34k8/dockerfile,wking/dockerfile