Fixed syntax errors, PEP8.
Removed set_services function.

Removed
-------
* Removed the unused set_services function.

Added
-----
* New keyword, *if_exists*, for:
  - register_component_class
  - register_component_classes
  provides guidance on what to do if a class is already registered.
Changed to delete services before test setup.
Changed package setup for unit tests to use new methods.
Removed unused import statement.
Fixed unit tests that used xy-indexing.