* adding function convnet example
* add unit test
* update test
* update example
* wip
* move error from experiment to tune
* wip
* Fix checkpoint deletion
* updating code
* adding smoke test
* updating pbt guide
* formatting
* fix build
* add best checkpoint analysis util
* update test
* add comments
* remove class api
* fix example
* add setup and teardown to tests
* formatting
* Update python/ray/tune/tests/test_trial_scheduler_pbt.py
Co-authored-by: Kai Fricke <kai@anyscale.com>
Co-authored-by: Richard Liaw <rliaw@berkeley.edu>
