Bitcoin-Qt: massive header and cpp cleanup

- try to enforce the same style to all Qt related files
- remove unneeded includes from the files
- add missing Q_OBJECT, QT_BEGIN_NAMESPACE / QT_END_NAMESPACE
- prepares for a pull-req to include Qt5 compatibility

src/qt/bitcoin.cpp

@@ -1,6 +1,9 @@
 /*
  * W.J. van der Laan 2011-2012
  */
+
+#include <QApplication>
+
 #include "bitcoingui.h"
 #include "clientmodel.h"
 #include "walletmodel.h"
@@ -11,7 +14,6 @@
 #include "ui_interface.h"
 #include "paymentserver.h"
 
-#include <QApplication>
 #include <QMessageBox>
 #include <QTextCodec>
 #include <QLocale>