SOME CHANGES IN GRASS 5.7/6.0

- G_gui() - new, generates GUI for command, it is run by default if no
            parameters were specified on command line; terminal interface
            may be forced by setting variable GRASS_UI_TERM
- GISLIB 
  - G_warning(), G_fatal_error() - send mail only if eviroment variable
                                   GRASS_ERROR_MAIL is set
  - G_debug() - new, print debugging info on selected level
  - G_plot_icon() - new, plot selected mark
- DBMI 
  - dbmscap file is not used, drivers are searched in dist.$ARCH/driver/db
  - new dbf driver
- vector library completely rewritten (multilayer, multiformat, 3D)
- new make system
- programmer's manual integrated into source code (doxygen)

