Set window title only once at startup

Putting image info in the title predates the info bar; it no longer seems
necessary.

Fixes issue #318.

main.c

@@ -350,18 +350,9 @@ void bar_put(win_bar_t *bar, const char *fmt, ...)
 void update_info(void)
 {
 	unsigned int i, fn, fw;
-	char title[256];
 	const char * mark;
 	win_bar_t *l = &win.bar.l, *r = &win.bar.r;
 
-	/* update window title */
-	if (mode == MODE_THUMB) {
-		win_set_title(&win, "sxiv");
-	} else {
-		snprintf(title, sizeof(title), "sxiv - %s", files[fileidx].name);
-		win_set_title(&win, title);
-	}
-
 	/* update bar contents */
 	if (win.bar.h == 0)
 		return;

window.c

@@ -464,9 +464,6 @@ void win_draw_rect(win_t *win, int x, int y, int w, int h, bool fill, int lw,
 
 void win_set_title(win_t *win, const char *title)
 {
-	if (title == NULL)
-		title = "sxiv";
-
 	XStoreName(win->env.dpy, win->xwin, title);
 	XSetIconName(win->env.dpy, win->xwin, title);