Improve file dialogs

- Fixes #314
- Adds file extensions to sound and image browsing
- Some options no longer default to our config dir
- Always add a shortcut to our config dir
- Remove broken 'last_dir' functionality, gtk already knows recent

src/fe-gtk/gtkutil.h

@@ -21,16 +21,10 @@
 #define HEXCHAT_GTKUTIL_H
 
 #include <gtk/gtk.h>
+#include "../common/fe.h"
 
 typedef void (*filereqcallback) (void *, char *file);
 
-#define FRF_WRITE 1
-#define FRF_MULTIPLE 2
-#define FRF_ADDFOLDER 4
-#define FRF_CHOOSEFOLDER 8
-#define FRF_FILTERISINITIAL 16
-#define FRF_NOASKOVERWRITE 32
-
 void gtkutil_file_req (const char *title, void *callback, void *userdata, char *filter, char *extensions, int flags);
 void gtkutil_destroy (GtkWidget * igad, GtkWidget * dgad);
 void gtkutil_destroy_on_esc (GtkWidget *win);