text: Title: Remove old datasets code and rewire with new datasets.load_* api
  Body: As a follow up to reworking the datasets API, we need to go through and remove redundant old code in these locations:
  
  - [x] `yellowbrick/download.py`
  
  - [ ] `tests/dataset.py`
  
  Part of this will be a requirement to rewire tests and examples as needed. Likely also there might be slight transformations of data in code that will have to happen
  
  @DistrictDataLabs/team-oz-maintainers
  