1/2002: Markus Neteler

 - have updated write routines to GRASS 5 functions (taken from i.rectify2)
 - have changed elev reading from CELL to raster_type to support
   also FP elevations

 
Bugs:
 - somewhere the map_type is undefined in an underlying function (can't 
   identify), so I added G_suppress_warnings(1) at top of rectify.c
   -> the module works well

 - when DEBUG3 is activated, the module silently stops in exec.c at
   select_current_env() (line 87). Why???
   However, not a real bug. Seems to be a problem of exit status or
   whatever.