[GRASS5] r3.info: range flag added

[Markus Neteler]

Hi,

recently Benjamin asked for r3.info ranges, I have
added this now in 6.1-CVS:

#slovakia3d data:

r3.info -r precip3d.500z50
min=525.456909
max=1801.444336

Hope the result is right :-)

Now it should be much easier to find the right values
for NVIZ isosurfaces.

Markus