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.

TactilityCore/Source/Log.h

@@ -2,7 +2,14 @@
 
 #include "LogMessages.h"
 
-#if CONFIG_SPIRAM_USE_MALLOC == 1 or not defined(ESP_PLATFORM)
+#ifdef ESP_TARGET
+#include <esp_log.h>
+#else
+#include <cstdarg>
+#include <cstdio>
+#endif
+
+#if not defined(ESP_PLATFORM) or (defined(CONFIG_SPIRAM_USE_MALLOC) && CONFIG_SPIRAM_USE_MALLOC  == 1)
 #define TT_LOG_ENTRY_COUNT 200
 #define TT_LOG_MESSAGE_SIZE 128
 #else
@@ -35,12 +42,6 @@ LogEntry* copyLogEntries(unsigned int& outIndex);
 
 } // namespace tt
 
-#ifdef ESP_TARGET
-#include "esp_log.h"
-#else
-#include <cstdarg>
-#include <cstdio>
-#endif
 
 #ifdef ESP_TARGET
 

TactilityCore/Source/StringUtils.cpp

@@ -78,4 +78,13 @@ std::string join(const std::vector<std::string>& input, const std::string& delim
     return stream.str();
 }
 
+std::string removeFileExtension(const std::string& input) {
+    auto index = input.find('.');
+    if (index != std::string::npos) {
+        return input.substr(0, index);
+    } else {
+        return input;
+    }
+}
+
 } // namespace

TactilityCore/Source/StringUtils.h

@@ -66,5 +66,9 @@ std::basic_string<T> lowercase(const std::basic_string<T>& input) {
     return std::move(output);
 }
 
+/**
+ * @return the first part of a file name right up (and excluding) the first period character.
+ */
+std::string removeFileExtension(const std::string& input);
 
 } // namespace

TactilityCore/Source/Timer.h

@@ -34,7 +34,7 @@ public:
      * @param[in] callback The callback function
      * @param callbackContext The callback context
      */
-    Timer(Type type, Callback callback, std::shared_ptr<void> callbackContext);
+    Timer(Type type, Callback callback, std::shared_ptr<void> callbackContext = nullptr);
 
     ~Timer();