Refactor app access (#205)

- Use `tt::app::` functions to start/stop apps and get current app(context) instead of using loader everywhere
- Removed `tt_service_loader.*` from TactilityC
- Created `tt_app_stop()` for TactilityC
- Bumped version to 0.3.0 to prepare for upcoming release

Tactility/Source/app/wificonnect/View.cpp

@@ -25,7 +25,7 @@ void View::resetErrors() {
 }
 
 static void onConnect(TT_UNUSED lv_event_t* event) {
-    auto wifi = optWifiConnect();
+    auto wifi = std::static_pointer_cast<WifiConnect>(getCurrentApp());
     auto& view = wifi->getView();
 
     wifi->getState().setConnectionError(false);