This change is actually untested as there is currently no support
in the lv6 interpreters to do something with #reset

(the doc say it is the case by default, but...)

remotely

Also, the pdf content was written in the gnuplot.log file.

Add tests

Indeed, it is not lutils fault when it occurs.

Indeed, it seems it is not supported by gnuplot anymore (at least it
is disabled in the version shipped with debian 8).

and collect the stdout lines into a list (requires sed)

Also add an entete2 command that accept multi-line comments