set pm3d explicit

[Petr M. <mi...@ph...>]

Until now, how you had to type
	set pm3d; splot x*y with pm3d
I've just committed a patch which allows
	splot x*y with pm3d
anytime. Thus, "set pm3d explicit" is on after gnuplot startup and after
'reset'.

For compatibility (historical) reasons (color filled pm3d plot combined with
mesh line plot): commands "set pm3d;" and "set pm3d at X other_opts;" switch
pm3d to "implicit". No change for "set pm3d map" which changes "set style".

In rare cases, you may have to add "implicit|explicit" option to your
scripts. Actually I wonder whether whether it is needed at all to draw
the combined surface mesh + color surface (in one shot)...

---
PM