Updates warnings, etc.

[jGaboardi]

This PR provides solutions for several newish warning cropping up in CI:

• fill_diagonal vs. insert_diagonal
• numpy.int vs. int
• explicitly use drop_islands={True, False} in testing
• provide a to_adjlist_kws keyword argument for functions in adjtools.py to interface with W.to_adjlist()
• ensure the newHaven dataset is available for testing. this was failing for me locally.

[codecov]

Codecov Report

Merging #478 (a2e8ca2) into master (ac132a1) will increase coverage by 0.0%.
The diff coverage is 84.2%.

@@          Coverage Diff           @@
##           master    #478   +/-   ##
======================================
  Coverage    79.3%   79.4%           
======================================
  Files         122     121    -1     
  Lines       12971   12973    +2     
======================================
+ Hits        10291   10299    +8     
+ Misses       2680    2674    -6     

Impacted Files	Coverage Δ
libpysal/io/iohandlers/tests/test_db.py	50.0% <0.0%> (-5.6%)	⬇️
libpysal/weights/adjtools.py	84.9% <88.9%> (ø)
libpysal/weights/spatial_lag.py	93.0% <100.0%> (ø)
libpysal/weights/tests/test_adjlist.py	100.0% <100.0%> (ø)
libpysal/weights/tests/test_util.py	99.1% <100.0%> (ø)
libpysal/weights/util.py	78.1% <0.0%> (-0.4%)	⬇️
libpysal/weights/weights.py	80.9% <0.0%> (-0.4%)	⬇️
libpysal/__init__.py
libpysal/_version.py	40.7% <0.0%> (+2.7%)	⬆️
libpysal/examples/base.py	67.8% <0.0%> (+3.4%)	⬆️

[jGaboardi]

Let's wait a day or so to merge this in case @sjsrey has any input.

[jGaboardi]

What are y'all's thoughts for a v4.7.1 patch release?