w: Adjust command width

w: Adjust command width

w would error out if the window size was smaller than 71 or some
other fields through environment grew too big. The code was a little
convoluted as well. The minimum length for command was 3, which is
pretty useless.

This change does the following:
 w doesn't care by default the window size
 w will adjust the command length up and down, to a minimum of 7
characters.
 if the fields don't fit, w will line-wrap each line.

The idea being its better the line-wrap than it is to error out.

References: https://bugs.debian.org/183394

Signed-off-by: Craig Small <csmall@enc.com.au>