Refactored app registration (#362)

`AppManifest` is renamed to `AppRegistration` because it was confusing with the actual app manifest (as in: the properties file).
Instead of passing a pointer, we're now passing the struct by value.
I also moved some files around in `TactilityC/`.

TactilityC/Source/tt_init.cpp

@@ -2,7 +2,6 @@
 
 #include "tt_app.h"
 #include "tt_app_alertdialog.h"
-#include "tt_app_manifest.h"
 #include "tt_app_selectiondialog.h"
 #include "tt_bundle.h"
 #include "tt_file.h"