- Adds the deriveQualifiedKey and deriveKey methods to ca;culate the key
  with the prefix -- supporting deterministic internal operation and
loosely coupled white box testing
- Adds tests for remove, deriveKey, and key replacement
- Splits the add tests into 3 scenerios -- add JSON, add string, and add
  integer
- Remove the test stubs for get, set, and clearAll to properly test the
  underlying methods
- Adds Vim swap files to .gitignore
- Checks the key list in every applicable scenario
- Clears local storage between test runs