Drop "private" subfolders

"private" subfolders violate the structure of the project,
since the existence of all other subfolders is based on a
different principle.
In addition, there is no clear line between "private" and
"non private".

src/base/bittorrent/torrentcreatorthread.cpp

@@ -46,7 +46,7 @@
 #include "base/utils/fs.h"
 #include "base/utils/io.h"
 #include "base/utils/string.h"
-#include "private/ltunderlyingtype.h"
+#include "ltunderlyingtype.h"
 
 namespace
 {