Makefile: Added missing png library to linker options (issue 141)

Fix the minimum screen size not enforced when resizing window (since r705)
Fix the mouse cursor position when changing pixel size (since r705)
In fileselector, the image preview now enforces "safe colors". (issue 116)


git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@716 416bcca6-2ee7-4201-b75f-2eb2f807beb1

palette.h

@@ -28,3 +28,9 @@ void Set_palette_RGB_scale(int);
 // The resulting range is [0-255]
 byte Round_palette_component(byte comp);
 
+/*!
+  Adds 4 menu colors in the current palette.
+  @param color_usage An up-to-date color usage table (byte[256]) (read only)
+  @param not_picture 0 if the caller is the palette screen, 1 if it's a preview in the file selector.
+*/
+void Set_nice_menu_colors(dword * color_usage,int not_picture);