Do not print private key to console
Drop all references to twisted.
Drop Twisted from requirements.
Upgrade tornado to version 4.0.2.
Remove logging of settings
Merge pull request #751 from dionyziz/hide_private_key

Do not print private key to console
Merge pull request #753 from Renelvon/bump_tornado

Upgrade tornado to version 4.0.2.
Merge pull request #752 from Renelvon/drop_twisted

Drop twisted from requirements