Allow tls skip verify option

[EinAeffchen]

I am currently in a situation where I have to create an ssh tunnel to deploy eggs via the scrapyd client, which causes me to deploy through localhost and in turn leads to this error:

Deploy failed: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: self-signed certificate (_ssl.c:997)>

It would be great if I could just set tls_skip_verify in the scrapy.cfg and deploy anyways.