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/Source/Semaphore.cpp

@@ -1,6 +1,6 @@
-#include "Semaphore.h"
-#include "Check.h"
-#include "CoreDefines.h"
+#include "Tactility/Semaphore.h"
+#include "Tactility/Check.h"
+#include "Tactility/CoreDefines.h"
 
 namespace tt {