[dreamhost|dns] remove silly debugging code
[dreamhost|dns] do not delete the do-not-delete record when testing
[dreamhost|dns] added test helpers

Also, use a helper instead of hardcoding the test domain in the tests
[dreamhost|dns] Added README.md file documenting testing procedure
[dreamhost|dns] Removed get_record request

- The request does not map to a Dreamhost API request, remove it.
- Updated the Records collection to use list_records instead of
  get_record in Records#get
- Added Records collection model test
[dreamhost|dns] refactor dns requests tests

Every request now has it's own test file.