moved typedefs to beginning of files to solve some include problems

splitted authenticator to have a separate implementation for each auth_method_t
using va_copy to clone va_lists, should fix proplems on AMD64
some other cleanups

src/libstrongswan/crypto/prf_plus.h

@@ -24,12 +24,10 @@
 #ifndef PRF_PLUS_H_
 #define PRF_PLUS_H_
 
+typedef struct prf_plus_t prf_plus_t;
 
 #include <crypto/prfs/prf.h>
 
-
-typedef struct prf_plus_t prf_plus_t;
-
 /**
  * @brief Implementation of the prf+ function described in IKEv2 RFC.
  *