the funpack.config logger an explicit log level, which will cause it to not
use the level set on ancestor loggers. Assume that logger has not been
configured, and set it to NOTSET, so that parent logger settings will be used.

ENH: Option to ignore redundancy check for uncategorised/unknown columns

See merge request fsl/funpack!82

append/prepend process

lists in data frames, and merging dataframes with different index dtypes

improve/fix associative test

function. Implemented for pairwise version, need to do matrix version.
Change to processing core function signatures

Bf/empty columns

See merge request fsl/funpack!81

Update cleaning options to support non-numeric

Closes #23

See merge request fsl/funpack!80