Sets the column expand ratio for given column.
Expand ratios can be defined to customize the way how excess space is
divided among columns. Table can have excess space if it has its width
defined and there is horizontally more space than columns consume
naturally. Excess space is the space that is not used by columns with
explicit width (see
#setColumnWidth(Object,int)) or with natural
width (no width nor expand ratio).
By default (without expand ratios) the excess space is divided
proportionally to columns natural widths.
Only expand ratios of visible columns are used in final calculations.
Column can either have a fixed width or expand ratio. The latter one set
is used.
A column with expand ratio is considered to be minimum width by default
(if no excess space exists). The minimum width is defined by terminal
implementation.
If terminal implementation supports re-sizable columns the column becomes
fixed width column if users resizes the column.