Changed a lot of platform-specific code to "simplify" it:

A Unix-like system is now considered the default.
The number of platform-specific blocks is down to:
   win32: 13, watcomc: 3, linux: 4, macosx: 16, amigaos4: 8, beos/haiku: 1
Removed linux.c, implemented the relevant functions for all platforms.
(win32) In Stats screen, included free memory report
(macosx) Conversion_ANSI: Fixed the __macosx__ with wrong case from my former 'fix', sorry.
(macosx) readline.c : Removed a manual "Update_necessaire=1", because normally
all calls to UpdateRect() will set this flag already. Don't hesitate to call 
Flush_Update() anywhere where it's lacking, but you shouldn't put it inside a  #ifdef __macosx__
(win32) Packaging: 'make ziprelease' now includes libpng13.dll and zlib1.dll
(win32) Hacked something to resolve naming conflict of MOD_SHIFT constants with windows.h
(all) Resolution: Fixed the black space that appeared between button and label,
the memory overwrite also caused resolutions above number 2 to disappear from list.
 
Tested fine on Linux (without TTF) and Windows


git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@345 416bcca6-2ee7-4201-b75f-2eb2f807beb1

io.h

@@ -43,8 +43,8 @@ void Extraire_chemin(char *Destination, const char *Source);
 
 char * Position_dernier_slash(const char * Chaine);
 
-#if defined(__linux__)||defined(__BEOS__)||defined(__HAIKU__)
-  #define SEPARATEUR_CHEMIN "/"
-#else
+#if defined(__amigaos4__) || defined(__WIN32__)
   #define SEPARATEUR_CHEMIN "\\"
+#else
+  #define SEPARATEUR_CHEMIN "/"
 #endif