Add HTTPS Server

[philippgille]

Instead of just HTTP, HTTPS should be possible as well.

• https://github.com/denji/golang-tls
• https://golang.org/src/crypto/tls/generate_cert.go
• https://github.com/kabukky/httpscerts

[philippgille]

Also check out this PR on kabukky/httpscersts: kabukky/httpscerts#1
Or the fork the PR is originating from: https://github.com/gerald1248/httpscerts/tree/diskless

Also check out how Caddy does its TLS self-signing (it's similar to the above): https://github.com/mholt/caddy/blob/master/caddytls/selfsigned.go