Moved pthreadtypes header to its correct location

It seems that this header should reside in the bits folder, which
should prevent type redefinition errors from happening since
it will mask the systems header.

Fixes #485

Author: zvonimir

share/smack/include/pthreadtypes.h renamed to share/smack/include/bits/pthreadtypes.h

@@ -4,7 +4,7 @@
 #ifndef PTHREAD_H
 #define PTHREAD_H
 
-#include "pthreadtypes.h"
+#include "bits/pthreadtypes.h"
 
 // model mutex:
 //  0 = unlocked,