tabulated-list: extend truncation into next align-right column
See discussion on:
https://lists.gnu.org/archive/html/emacs-devel/2016-10/msg01101.html
* lisp/emacs-lisp/tabulated-list.el
(tabulated-list--near-rows): New variable.
(tabulated-list-print, tabulated-list-set-col): Use it.
(tabulated-list--col-local-max-widths): New defsubst.
(tabulated-list-print-col): Use it. If the next column is
align-right, and has some space left then don't truncate to width,
use some of the available space from the next column.