Column header group flags

MTBL_CHG_FLAG_NOCOLHEADERS	The column headers are omitted, only the column header group is displayed.
MTBL_CHG_FLAG_NOINNERHORZLINE	The inner horizontal line is omitted. See also: Custom lines.
MTBL_CHG_FLAG_NOINNERVERTLINES	The inner vertical lines are omitted. See also: Custom lines.
MTBL_CHG_FLAG_TXTALIGN_LEFT	The text of the column header group is left aligned. See also: Extended text alignment.
MTBL_CHG_FLAG_TXTALIGN_RIGHT	The text of the column header group is right aligned. See also: Extended text alignment.