COL_COLUMN and COL_ROW fill column by column (or row by row
respectively), given the terminal width and how many space between
columns. All cells have equal width.
Strings are supposed to be in UTF-8. Valid ANSI escape strings are OK.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>