Add ignore-ssl and ac-file options to CLI

Fixes #54

Both options are set either in the config file or as runtime
arguments.

ignore-ssl option allows connections without checking SSL
certificates

The ca-file option provides a CA file for SSL authentication

These options are mutually exclussive

Both options are checked and dealed with early on. The default
behavior is raise SSL errors if no authetnication is provided

In case of an SSL error, kamaki stops and notifies the user
except if they use the ignore-ssl option