Cleanup (#43)

- Updated README.md, screenshot layout
- Cleanup of incorrect `TT_UNUSED` usage

app-sim/src/hello_world/hello_world.c

@@ -2,7 +2,7 @@
 #include "services/loader/loader.h"
 #include "ui/toolbar.h"
 
-static void app_show(TT_UNUSED App app, lv_obj_t* parent) {
+static void app_show(App app, lv_obj_t* parent) {
     lv_obj_t* toolbar = tt_toolbar_create_for_app(parent, app);
     lv_obj_align(toolbar, LV_ALIGN_TOP_MID, 0, 0);
 

app-sim/src/lvgl_task.c

@@ -19,7 +19,7 @@ static uint32_t task_max_sleep_ms = 10;
 static QueueHandle_t task_mutex = NULL;
 static bool task_running = false;
 
-static void lvgl_task(TT_UNUSED void* arg);
+static void lvgl_task(void* arg);
 
 static bool task_lock(int timeout_ticks) {
     assert(task_mutex != NULL);