add = function ( colIdx, name ) {
			var includeIn = columns[ colIdx ].includeIn;

			if ( $.inArray( name, includeIn ) === -1 ) {
				includeIn.push( name );
			}
		}
Create the internal `columns` array with information about the columns
for the table. This includes determining which breakpoints the column
will appear in, based upon class names in the column, which makes up the
vast majority of this method.

@private