More refactoring of tools API test case.
Enhance the Tool Shed API to provide functions for retrieving and creating categories.
Add a Tool Shed API script that can be used to retrieve the current set of categories from a Tool Shed (e.g. the test Tool Shed) and create each of them in a local development Tool Shed.  This script can be used to streamline the process of creating a new development Tool Shed, populating it with categories expected in a public Tool Shed, and creating a new repository hierarchy that can be exported into a capsule and imported into the public Tool Shed.
Fix admin and library feature functional tests. Improve handling of checkbox parameters and multi-select inputs in functional tests.