Consider a simpler way of starting up Artio in sole library mode.

[RichardWarburton]

Design discussion issue.

A way to compose the FixEngine and a single FixLibrary operating in the same process. This should reduce the scope for errors for people using SOLE_LIBRARY_MODE, auto-configure to use aeron IPC and generally abstract / hide away the distinction between FixEngine and FixLibrary for people who only want to use a single threaded instance. Major design questions are around how to allow users of this composed object to hook their own code in nicely.