Refactor app launching (#174)

- Refactor the way apps work: Instead of a C interface, they are now C++ classes. The main reasoning is that attaching data to an app was cumbersome. Having different implementations for different kinds of apps was cumbersome too. (3 or 4 layers of manifest nesting for the TactilityC project)
- External apps are still written in C, but they get a createData/destroyData in their manifest, so:
- External apps now have their own manifest.
- All functions in the original AppManifest are removed and replaced by a single `createApp` function
- External apps now automatically register (each app individually!) when they run the first time. As a side-effect they become visible in the `AppList` app!
- Adapted all apps for the new interface.
- Adapted all internal logic for these changes (Gui, ViewPort, Loader, AppContext, AppInstance, etc.)
- Rewrote parts of Loader to use std::shared_ptr to make the code much safer.
- Added a refcount check for the `AppInstance` and `App` at the end of their lifecycle. Show warning if refcount is too high.

Tactility/Source/Tactility.cpp

@@ -64,7 +64,6 @@ namespace app {
         namespace screenshot { extern const AppManifest manifest; }
 #endif
 #ifdef ESP_PLATFORM
-    extern const AppManifest elfWrapperManifest;
     namespace crashdiagnostics { extern const AppManifest manifest; }
 #endif
 }
@@ -99,8 +98,7 @@ static const std::vector<const app::AppManifest*> system_apps = {
     &app::screenshot::manifest,
 #endif
 #ifdef ESP_PLATFORM
-    &app::crashdiagnostics::manifest,
-    &app::elfWrapperManifest, // For hot-loading ELF apps
+    &app::crashdiagnostics::manifest
 #endif
 };
 
@@ -109,11 +107,11 @@ static const std::vector<const app::AppManifest*> system_apps = {
 static void register_system_apps() {
     TT_LOG_I(TAG, "Registering default apps");
     for (const auto* app_manifest: system_apps) {
-        addApp(app_manifest);
+        addApp(*app_manifest);
     }
 
     if (getConfiguration()->hardware->power != nullptr) {
-        addApp(&app::power::manifest);
+        addApp(app::power::manifest);
     }
 }
 
@@ -121,7 +119,7 @@ static void register_user_apps(const std::vector<const app::AppManifest*>& apps)
     TT_LOG_I(TAG, "Registering user apps");
     for (auto* manifest : apps) {
         assert(manifest != nullptr);
-        addApp(manifest);
+        addApp(*manifest);
     }
 }