Some more namespace hygiene for "using decl;".

src/crypto/crypto.h

@@ -40,13 +40,13 @@
 #include <stdlib.h>
 #include <exception>
 
-using std::string;
 
 long int myatoi( const char *str );
 
 class PRNG;
 
 namespace Crypto {
+  using std::string;
 
   class CryptoException : public std::exception {
   public:

src/network/compressor.cc

@@ -36,6 +36,7 @@
 #include "dos_assert.h"
 
 using namespace Network;
+using std::string;
 
 string Compressor::compress_str( const string &input )
 {

src/network/transportfragment.h

@@ -39,11 +39,11 @@
 
 #include "transportinstruction.pb.h"
 
-using std::vector;
-using std::string;
-using namespace TransportBuffers;
-
 namespace Network {
+  using std::vector;
+  using std::string;
+  using namespace TransportBuffers;
+
   class Fragment
   {
   public:

src/network/transportsender.h

@@ -43,11 +43,11 @@
 #include "transportfragment.h"
 #include "prng.h"
 
-using std::list;
-using std::pair;
-using namespace TransportBuffers;
-
 namespace Network {
+  using std::list;
+  using std::pair;
+  using namespace TransportBuffers;
+
   /* timing parameters */
   const int SEND_INTERVAL_MIN = 20; /* ms between frames */
   const int SEND_INTERVAL_MAX = 250; /* ms between frames */

src/statesync/user.h

@@ -40,11 +40,11 @@
 
 #include "parseraction.h"
 
-using std::deque;
-using std::list;
-using std::string;
-
 namespace Network {
+  using std::deque;
+  using std::list;
+  using std::string;
+
   enum UserEventType {
     UserByteType = 0,
     ResizeType = 1