`Moran*.by_col()` methods deprecated?

[jGaboardi]

Similar to #229, the tests for the Moran*.by_col() methods have been deprecated and marked for removal "in the next release" (though that seems to have been ≈4 years ago), but is no actual indication the methods themselves are marked as such. For example, Moran_Tester.test_by_col() is marked deprecated, but there is nothing mentioning that in Moran.by_col().

Affected classes/tests:

• Moran.by_col() & Moran_Tester.test_by_col()
• Moran_Rate.by_col() & Moran_Rate_Tester.test_by_col()
• Moran_Local.by_col() & Moran_Local_Tester.test_by_col()
• Moran_Local_Rate.by_col() & Moran_Local_Rate_Tester.test_by_col()
• Moran_Local_BV.by_col() & Moran_Local_BV_Tester.test_by_col()

No corresponding test in test_moran.py:

• Moran_BV.by_col()

We should probably decide what's going on here sooner than later.