Project restructuring (fixes macOS builds) (#198)

- Create `Include/` folder for all main projects
- Fix some issues here and there (found while moving things)
- All includes are now in `Tactility/` subfolder and must be included with that prefix. This fixes issues with clashing POSIX headers (e.g. `<semaphore.h>` versus Tactility's `Semaphore.h`)

TactilityCore/Include/Tactility/RtosCompat.h

@@ -0,0 +1,13 @@
+#pragma once
+
+/**
+ * Compatibility includes for FreeRTOS.
+ * Custom FreeRTOS from ESP-IDF prefixes paths with "freertos/",
+ * but this isn't the normal behaviour for the regular FreeRTOS project.
+ */
+
+#ifdef ESP_PLATFORM
+#include "freertos/FreeRTOS.h"
+#else
+#include "FreeRTOS.h"
+#endif