add lv_components as src/extra and minor fixes

examples/widgets/spinner/lv_spinner_example_1.c

@@ -0,0 +1,12 @@
+#include "../../../lvgl.h"
+#if LV_USE_SPINNER
+
+void lv_ex_spinner_1(void)
+{
+    /*Create a Preloader object*/
+    lv_obj_t * spinner = lv_spinner_create(lv_scr_act(), 500, 60);
+    lv_obj_set_size(spinner, 100, 100);
+    lv_obj_align(spinner, NULL, LV_ALIGN_CENTER, 0, 0);
+}
+
+#endif