Address tutorial points of confusion (cleanlab#233)

* address tutorial points of confusion

* fix typo indices k --> num_classes - 1

Co-authored-by: Curtis G. Northcutt <curtis.northcutt@gmail.com>

Merge pull request cleanlab#125 from cgnorthcutt/release101

Update version to 1.0.1

cleanlab version 1.0 beta launch!

Merge branch 'master' of github.com:cgnorthcutt/cleanlab