Integrate better locking and a runner helper class.

Ensure that when a linear flow or derivatives is running
that it can not be modified by another thread at the same
time it is running by putting a lock around sensitive functions.

Also instead of using the raw task objects themselves
integrate a helper 'runner' class that provides useful
functionality that occurs before its tasks runs as well
as member variables that are associated with the contained
task.

This helper class currently provides the following:

- A uuid that can be returned to callers of the add
  method to identify there task (and later its results),
  allowing for multiple of the same tasks to be added.
- Automatic extraction of the needed required and optional
  inputs for the contained task.

Change-Id: Ib01939a4726155a629e4b4703656b9067868d8f3