* Use scipy.sparse array datastructure

* Add reminder to rm wrapper when scipy adds creation fns.

* Rm mention of np matrix from code comment.

* Update networkx/algorithms/bipartite/matrix.py

Co-authored-by: Stefan van der Walt <sjvdwalt@gmail.com>

Co-authored-by: Ross Barnowski <rossbar@berkeley.edu>
Co-authored-by: Stefan van der Walt <sjvdwalt@gmail.com>

* remove to/from_scipy_sparse_matrix

* skip geospatial example build

Co-authored-by: Mridul Seth <seth.mridul@gmail.com>
Co-authored-by: Mridul Seth <mail@mriduls.com>

* Add isort to pre-commit

* Run isort on all python files (except __init__.py ones)

* Fix return type in docstring of internal function.

* Rm explicit mention of numpy matrix from class docstrings.

* Fix return type of floyd_warshall_numpy docstring.

* Remove mention of numpy matrix from code comment.

* Fix simrank similarity internal docstring.

* Rm explicit mention of matrix in favor of 2D array.

* Update to_networkx_graph array exception wording.

* Remove extraneous mention of numpy matrix.

* Don't print array in exception message.

* Use toarray instead of todense in test suite.

toarray is less ambiguous and forward-compatible.

* Rm isinstance target and use from_numpy_array.

np.matrix is a sublcass of ndarray so there is no need to
explicitly include it in the isinstance tuple.

A more descriptive variable name for exceptions. This reduces local var naming conflicts when
\`e\` is used e.g. to represent edges as a loop variable.

* add special processing of `multigraph_input` upon graph init

Fixes: #4720

Adding a keyword argument `multigraph_input=True`
to a graph construction call should treat any incoming input data for
the graph as a dict-of-dict-of-dict multigraph data structure.

Previously the multigraph_input argument would be added to the graph
attribute dict and ignored when processing the input data.

* Change default and add tests

* make default try mgi=True, and if fails try mgi=False

* copy parameter docstring to main class

Co-authored-by: Ross Barnowski <rossbar@berkeley.edu>

* TST: Improve coverage of conversion module.

* WIP: Remove attr checks for graph/nodes?

* TST: remove to_dict_of_dict tests.