bug#54908: Make tabluated list tables more readable by adding some light column color to even columns

[Denes Kis]

Since columns have no separating lines, nor different colors, tables are often 
hard to read when the values are close to each other due to column sizes:

                2m 26.0s       5m 0.0s savehist-autosave
             8h 8m 12.5s 1d 0h 0m 0.0s clean-buffer-list
            11h 8m 12.7s 1d 0h 0m 0.0s run-hooks
           18h 28m 12.5s 1d 0h 0m 0.0s recentf-cleanup
               59m 29.6s    1h 0m 0.0s url-cookie-write-file

Adding some light background color to even numbered columns could alleviate 
this, because then it's easier to see where a column ends and where the data of 
the next column begins.