Tests written for the task pool library.

The task pool tests reside in the tests/common directory. They are divided into the following subdirectories:

• system: task pool system and stress tests. Stress tests may run for a long time, so they are not run unless the -l option is passed to the test executable.
• unit: task pool unit tests. These tests do not require a network connection.

The current task pool tests use the Unity test framework.