[GRASS5] NVIZ Documentation

[Bob Covill]

Hello,

I have finally applied the updated NVIZ documenation to CVS. Note that 
the documentation is layed out as a reference guide (not a howto guide). 
  I have left the scripting section untouched because scripting is still 
mostly not working. Also, the hints section still needs updating (I ran 
out of time). It is in this section where we could add sections for 
key-frame animation, encoding images (mpeg, etc), off-screen rendering, 
NVIZ related environment variables, etc.

Let me know if you find any errors, etc.

I have also updated the HTML->TCL help interface for NVIZ. This is 
activated from the Help button in the NVIZ GUI. The interface is a 
little cleaner and easier to use.

I have also applied an update to GS2.c in the ogsf library. The change 
catches errors from trying to load raster data that is outside the 
current region, doesn't exist in the mapset, or does not contain any 
data. Each of these conditions would cause NVIZ to crash and exit. The 
fix will catch these errors (hopefully) and exit more gracefully, with 
an approprite error message.

-- 
Bob Covill