do not block accepting connections

[munkyboy]

When using a plain TCP listener, goScanConnection creates some data structures and moves on to scan which is wrapped in a goroutine.

When using a TLS listener, goScanConnection does not return until the TLS handshake is complete. A lot can go wrong during this stage.

This change wraps goScanConnection in a goroutine to avoid blocking accepting the next connection.

[satta]

Please consider this PR, it will be appreciated by anyone looking to use the TLS functionality.