Iteration example in initialization and time loop

[eranschweitzer]

Summary

If merged this pull request will provide an example for how to perform iteration during:

• initialization
• a single time step

Proposed changes

• A new example is created, where two very tightly coupled federates successfully iterate to a converged solution both in initialization as well as throughout the co-simulation time steps.
• The code is slightly modified structurally (refactored) to allow for more reuse.

[eranschweitzer]

Closes #56