add lv_components as src/extra and minor fixes

examples/widgets/bar/lv_bar_example_1.c

@@ -0,0 +1,12 @@
+#include "../../../lvgl.h"
+#if LV_USE_BAR
+
+void lv_ex_bar_1(void)
+{
+    lv_obj_t * bar1 = lv_bar_create(lv_scr_act(), NULL);
+    lv_obj_set_size(bar1, 200, 20);
+    lv_obj_align(bar1, NULL, LV_ALIGN_CENTER, 0, 0);
+    lv_bar_set_value(bar1, 70, LV_ANIM_OFF);
+}
+
+#endif