Add extended support for zero? method. Will be used by helper methods that remove empty columns.
Add Table#row_mapper. Allow clients to set class that calls #map(row) to convert source rows to hashes or arrays.
Drop .rb in requires
Add renderers. Clients can set classes to control how cell values and column headers are displayed.
DRY-up column key conversion
Pass parent objects into Row, Column, and Columns to support logic that requires parent context
Add missing test classes
Add Column#rows and Column#cells
Reorder methods
Add Column#max
Add Column#precision
Remove trailing whitespace
Ensure key is a string
Use new initialize signatures
Actually, Columns needs Keys, not Column
Add Column#max
Add Column#delete
Add Row#source
Move delete to Columns from Column
Reorder move method