integrate VBA classification from `splot` into `mapclassify`

[jGaboardi]

• integrate VBA classification from splot into mapclassify
• Sunsetting splot splot#188 (comment)

[jGaboardi]

So based on the comments¹² in pysal/splot#188, we should migrate the VBA functionality over here to mapclassify. This should include the imports found in splot/mapping.py, but do we think those 6 functions should simply be plopped into their own module – something like vba.py? And there does seem to be some redundancy between splot's version of mapclassify_bin() and mapclassify's version of classify() – as discussed in pysal/splot#118.

Thoughts from anyone/everyone welcome.

Footnotes

1. Dani ↩

2. Serge ↩