quell some warnings with g_hash_table_new

quell some warnings with g_hash_table_new

* gdk/gdkcolor.c:
(gdk_colormap_new) (gdk_colormap_get_system):
quell some warnings with g_hash_table_new

* gtk/gtkaccelgroup.c (gtk_accel_group_add): free the GtkSignalQuery when
we're done with it

* gtk/itemfactory.c:
(gtk_item_factory_from_path):
(gtk_item_factory_create_item): free some strings

* gtk/gtklabel.c:
(gtk_label_finalize): free label->pattern when done
(gtk_label_parse_uline): null terminate pattern string, delete some duplicated
code

* gtk/testthreads.c: add #include <unistd.h> for sleep()

-Yosh