CHAPTER 2
The Room2 Hierarchy:

   The wizard gets the room2 features by including <room2.h> at the top of
   his file. She/he can switch between the modes by defining EXTD_ROOM
   before the include statement:
#define EXTD_ROOM
#include <room2.h>

   This picture shows the general structure and where you can find the code
   of room2:
                             wizroom.c
                                 |
                             (include)
                                 |
                          include/room2.h
                           /           \
               (inherit) / (EXTD_ROOM ?) \ (include)
                       /                   \
                 obj/room2           include/room-code2.h
                     |                 | | | | | | | | |
           (inherit std features) (inherit std & add features)
                     |                 | | | | | | | | |
         obj/room/<name_o_feature> obj/room/<name_o_feature>

   Addendum: On the left branch we would like to add some optional inherits
   and includes via defines but without EXTD_ROOM :-) See also page 31 (last
   page or https://nemesis.de/lpc/doc/room2/page31 .

   Changed/modified by Kiri in August 2016.