Split the API test suites into Item and List classes.
For organizational purposes, and to make it easy to select a particular

set of tests, the API test classes have been split into two. There are

now resource list tests in each test file (all named ResourceListTests),

and item tests (ResourceItemTests). By keeping the same name, there's no

guesswork. It's easy to just run a set of tests in a resource's test

file.
While in here, I removed some usage of test_scmtools from the new

classes, which were not really needed.

Unit tests pass.