General improvement to the utility test client

[analyticbastard]

A history command needs to be implemented to show issued orders.

Also, pressing enter must not yield invalid command.

A title and basic instructions should show up on startup.

[analyticbastard]

Commit ebf36cf9dc2e8f183ab0b0cd4190b8109aa4eb38 largely solves this issue.

I leave it open to implement commands necessary to request the outstanding orders list and the completed trades list of issue #25

[analyticbastard]

Completed with ae427ce