- Added support for `n_features_in_`
- Improved validation and added support for `feature_names_in_`
- Renamed `kwargs` to `metric_params` and added safety check
  for an empty dict
- Removed attributes set in init and deferred to properties
- Raised error if tree query is performed with too few samples
- Cleaned up some list/dict comprehension logic

…to hdbscan

…trics`"

This reverts commit cd1edc4.

- Removed internal minkowski metric parameter validation in favor
  of `sklearn.metrics` built-in handling
- Removed default argument and presence of `p` in hdbscan functions
- Now users must pass `p` in through `metric_params`, consistent w/
  other metrics such as `wminkowski` and `mahalanobis`
- Removed vestigial estimator check -- now supported via common tests
- Fixed bug where `boruvka_kdtree` algorithm's accepted metrics were
  based off of `BallTree` not `KDTree`
- Cleaned up lines with unused returns by indexing output of `hdbscan`
- Greatly expanded scope of algorithm/metric compatability tests
- Streamlined some other tests
- Delted commented out tests

Included temporary addition of homogeneity measure from
original library for debugging purposes