* Breaking changes
  * Renames ``HAbleT`` and ``HAbleOpsMixin`` to [``HableT``][dyce.h.HableT] and  [``HableOpsMixin``][dyce.h.HableOpsMixin].
      Use alternate spellings.
  * Removes deprecated non-flattening unary operation methods ``P.__neg__`` and ``P.__pos__``.
      Use, e.g., ``#!python P.umap(operator.__neg__)`` or ``#!python P(-h for h in p)`` instead.
  * Removes deprecated synonym methods ``H.even`` and ``H.odd``.
      Use  [``H.is_even``][dyce.h.H.is_even] and [``H.is_odd``][dyce.h.H.is_odd] instead.
  * Removes deprecated synonym package ``dyce.plt``.
      Use [``dyce.viz``][dyce.viz] instead.
  * Removes special case handling of ``H({})`` for addition and subtraction.
      Check for code that relied on, e.g., ``#!python h + H({})`` resolving to ``#!python h``.
      It is probably not correct.
      If the behavior is desired, consider eliminating empty histograms before performing calculations.
      E.G., ``#!python h1 + h2 if h2 else h1``.

      See also the [``sum_h`` function][dyce.h.sum_h], which ensures the result is always a histogram:

      ``` python
      >>> from dyce.h import sum_h
      >>> sum(())
      0
      >>> sum_h(())
      H({})

      ```

      Note, however, that sums including empty histograms will be always result in empty histograms:

      ``` python
      >>> from dyce import H
      >>> hs = (H(6), H(6), H(6), H({}))
      >>> sum_h(hs)
      H({})

      ```

      If a different result was desired, adapting our advice from above would yield something like:

      ``` python
      >>> sum_h(h for h in hs if h)
      H({3: 1, 4: 3, 5: 6, 6: 10, ..., 16: 6, 17: 3, 18: 1})

      ```
* Other changes
  * Documentation overhaul including augmented examples and reorganized images and JavaScript.
  * Fixed ``H({}).format()`` bug.
  * Adds [``beartype``](https://github.com/beartype/beartype) runtime type checking.
  * *Maintains* support for Python 3.7 (for now).