Deferred processes & chaining nested promises

This release comes with some real-world tests, added to mimic the functionality of real-world usage of this library.

In the unit tests you'll see some lazy-searching over data structures that involve multiple nested promises. There are no backwards breaking changes in this release, but to achieve this functionality, the Deferred class can now be assigned processes to execute as part of its task.

As always, have fun and stay productive!