-Introduce new Requester_window to ask the user to enter a single value

-Reduce colors in the palette screen is now a dropdown for easy access to usual values. "Other" option opens a requester to enter a custom one if needed
-Some cleanup to make things a little more readable
-Build fixes after versionning system revert


git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@1090 416bcca6-2ee7-4201-b75f-2eb2f807beb1

windows.h

@@ -71,6 +71,7 @@ void Print_counter(short x,short y,const char * str,byte text_color,byte backgro
 byte Confirmation_box(char * message);
 void Warning_message(char * message);
 void Verbose_error_message(char * message);
+int Requester_window(char* message, int initial_value);
 
 void Display_image_limits(void);
 void Display_all_screen(void);