Removed some unneeded dependencies to speed up compile.

Code "cleanup": Functions that create a button now return its address.
This helps reduce the number of files that use the globals "Fenetre_Liste_boutons_*"


git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@642 416bcca6-2ee7-4201-b75f-2eb2f807beb1

graph.h

@@ -41,7 +41,6 @@ void Afficher_pixel(word X,word Y,byte Couleur);
 
 void Afficher_pinceau(short X,short Y,byte Couleur,byte Preview);
 void Effacer_pinceau(short X,short Y);
-void Effacer_curseur(void);
 
 void Redimentionner_image(word Largeur_choisie,word Hauteur_choisie);