Further reduce header dependencies

This commit removes the dependency of serialize.h on PROTOCOL_VERSION,
and makes this parameter required instead of implicit. This is much saner,
as it makes the places where changing a version number can have an
influence obvious.

src/qt/bitcoin.cpp

@@ -8,6 +8,7 @@
 #include "guiutil.h"
 
 #include "init.h"
+#include "ui_interface.h"
 #include "qtipcserver.h"
 
 #include <QApplication>

src/qt/messagepage.cpp

@@ -91,7 +91,7 @@ void MessagePage::on_signMessage_clicked()
         return;
     }
 
-    CDataStream ss(SER_GETHASH);
+    CDataStream ss(SER_GETHASH, 0);
     ss << strMessageMagic;
     ss << ui->message->document()->toPlainText().toStdString();
 

src/qt/qtipcserver.cpp

@@ -7,6 +7,7 @@
 #include <boost/tokenizer.hpp>
 #include <boost/date_time/posix_time/posix_time.hpp>
 
+#include "ui_interface.h"
 #include "util.h"
 #include "qtipcserver.h"
 

src/qt/walletmodel.cpp

@@ -4,6 +4,7 @@
 #include "addresstablemodel.h"
 #include "transactiontablemodel.h"
 
+#include "ui_interface.h"
 #include "wallet.h"
 #include "walletdb.h" // for BackupWallet