[GRASSLIST:24] r3.* modules update and history support

[Sören Gebbert]

Dear developers and users,
yesterday i submitted some changes to grass-6.1-cvs
that may interest you.

The modules: r3.out.vtk, r3.to.rast and r.to.rast3
now counting the depths from bottom to the top,
the behaviour bevor was wrong i think.

Those modules and r3.cross.rast now support different region settings.
The 2d and 3d region settings don't have to be equal anymore (the resolution).
If the regions are different, a message will be printed
which resolution (2d or 3d) are changed within the program 
(this won't effect the current region settings).

And a new shiny feature is the history support for 
raster3d maps. :) 
A history file will automatically created for new maps. 
r3.info is now able to show the history.

Bug-reports , suggestions and stuff are always welcome.

Best regards
Soeren