--linebuffer implemented

[Ole Tange]

--linebuffer is now implemented in git clone
git://git.savannah.gnu.org/parallel.git

It is sort of in between --ungroup and --group:

--ungroup does not guard against having half a line coming from job1
and half a line coming from job2, but prints out immediately.

--group only prints out when the job is finished - thus jobs will not be mixed.

--linebuffer guards against having half a line coming from job1 and
half a line coming from job2, but prints out when it has a full line.
It is slower than --group and much slower than --ungroup.

I will let Svenne Krap (who asked for the option) to come up with a
good example of when this is needed.


/Ole