Introduce test for smallest possible test to aid archaeology
Swap public static state for private instance state
Remove redundant clear() method
Encapsulate Random state, no need for it to be public
Encapsulate target line number for GOTO
Reduce public API, no need for so many public methods
Test for the degenerate case of the "too small" maze
Move banner insertion to final section to aid archaeology
Introduce explicit buildEntrance [to the maze] method