[Bug 134] Drop the "environment" concept.

Instead, allow specifying connection parameters on the CLI.
[Bug 134] Use tddium_client with noverify support
Add insecure mode.

Conditionally allow connecting to a server with an untrusted cert.

Allow setting connection parameters using environment variables.

Dup the error message to get around this issue in highline (fix not yet
published): https://github.com/JEG2/highline/pull/81