v0.0.19

• Fixes a bug with HNMFk checkpointing where if continuing from checkpoint on a HPC system, not all nodes would be free on the job queue due to the bug.
• Fixes a bug with BST post-order search where the order was incorrect.
• Adds BST in-order search capability. NMFk hyper-parameter changed accordingly:

k_search_method : str, optional
Which approach to use when searching for the rank or k. The default is "linear".

* ``k_search_method='linear'`` will linearly visit each K given in ``Ks`` hyper-parameter of the ``fit()`` function.
* ``k_search_method='bst_post'`` will perform post-order binary search. When an ideal rank is found, determined by the selected ``predict_k_method``, all lower ranks are pruned from the search space.
* ``k_search_method='bst_pre'`` will perform pre-order binary search. When an ideal rank is found, determined by the selected ``predict_k_method``, all lower ranks are pruned from the search space.
* ``k_search_method='bst_in'`` will perform in-order binary search. When an ideal rank is found, determined by the selected ``predict_k_method``, all lower ranks are pruned from the search space.