1) ReadScore(char *) instead of (void) so I can call it with a file name
 from MergeScore().
2) Enable password for VMS (trivial implementation)
3) Merging option. Password only is required.
4) Superuser option implemented (score file creation).
5) MAKE.COM -- Compilation relies on X11_ROOT:[INCLUDE] for some of the include
 file ( PARAM.H etc...) ; other .H (XPM.H) and .OLB libraries assumed to be in
 SYS$LIBRARY: . 
6) Global score file rest on the existence of the logical SOKOBAN_SCORES . 
 This logical should point onto a directory where the score files and saved
 games will reside. Note that for VMS, this directory should be set as W:RWE
 ; do not put any DELETE in case of problems ... You can also got for an ACL
 as (IDENT=[*,*],ACCESS=R+W...). Note that SOKOBAN_SCORES may be defined as
 SYS$LOGIN which would make the game function as before ...



Todo : 
------
 o Eventually should check the path SYS$LIBRARY and some X11_ROOT:[*] path in 
 .COM
 o Be sure everything remaind compatible with OpenVMS VAX and older VAX VMS
 version.