[#22] Add Helmet middleware;

[kirilknysh]

Before:

HTTP/1.1 200 OK
X-Powered-By: Express
Accept-Ranges: bytes
Cache-Control: public, max-age=0
Last-Modified: Tue, 15 Aug 2017 13:55:08 GMT
ETag: W/"11c7-15de62d3260"
Content-Type: text/html; charset=UTF-8
Content-Length: 4551
Date: Fri, 25 Aug 2017 14:52:18 GMT
Connection: keep-alive

After:

HTTP/1.1 200 OK
X-Frame-Options: SAMEORIGIN
Strict-Transport-Security: max-age=15552000; includeSubDomains
X-Download-Options: noopen
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Accept-Ranges: bytes
Cache-Control: public, max-age=0
Last-Modified: Tue, 15 Aug 2017 13:55:08 GMT
ETag: W/"11c7-15de62d3260"
Content-Type: text/html; charset=UTF-8
Content-Length: 4551
Date: Fri, 25 Aug 2017 15:07:05 GMT
Connection: keep-alive

Closes #22

[DaQuirm]

Looks like X-Powered-By didn't make it 😞

[DaQuirm]

LGTM, but has to undergo full gunslinger testing IMHO

[kirilknysh]

Definitely, testing first!

[DaQuirm]

Tested, works well with red wine 🍷
See #30