getApi() loses reference to NgrokClient when called in separate module

[Collin-St]

When calling getApi() from a module separate from where ngrok.connect() was called, reference to NgrokClient is lost and getApi() returns null.

getApi() should:

• retain reference to NgrokClient, or be able to recreate it
• return a working instance of NgrokClient for an ngrok process running outside of the node library