Use 'Connection#connect' in tests

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
Remove 'Connection#attemptToConnect'

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
Merge pull request #44 from jvirtanen/cleanups/connection-attempt-to-connect

Remove 'Connection#attemptToConnect'