Make imgcursor a config variable.

Previously, the value of imgcursor was determined by where a pointer
binding was set to a ci_cursor_navigate. If it was then the pointer
would change to left/right arrows depending on the position relative to
the window. Now the user has full control of over it which also allows
them to preserve the behavior in case they wrap the function.

config.def.h

@@ -164,4 +164,9 @@ static const button_t buttons[] = {
 	{ 0,            5,                g_zoom,               -1 },
 };
 
+/* mouse cursor on left, middle and right part of the window */
+static const cursor_t imgcursor[3] = {
+	CURSOR_LEFT, CURSOR_ARROW, CURSOR_RIGHT
+};
+
 #endif

main.c

@@ -92,10 +92,6 @@ timeout_t timeouts[] = {
 	{ { 0, 0 }, false, clear_resize },
 };
 
-cursor_t imgcursor[3] = {
-	CURSOR_ARROW, CURSOR_ARROW, CURSOR_ARROW
-};
-
 /**************************
   function implementations
  **************************/
@@ -917,14 +913,6 @@ int main(int argc, char *argv[])
 	filecnt = fileidx;
 	fileidx = options->startnum < filecnt ? options->startnum : 0;
 
-	for (i = 0; i < ARRLEN(buttons); i++) {
-		if (buttons[i].cmd == i_cursor_navigate) {
-			imgcursor[0] = CURSOR_LEFT;
-			imgcursor[2] = CURSOR_RIGHT;
-			break;
-		}
-	}
-
 	win_init(&win);
 	img_init(&img, &win);
 	arl_init(&arl);