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/csvmodelwriter.h

@@ -14,6 +14,7 @@ QT_END_NAMESPACE
 class CSVModelWriter : public QObject
 {
     Q_OBJECT
+
 public:
     explicit CSVModelWriter(const QString &filename, QObject *parent = 0);
 
@@ -36,11 +37,6 @@ private:
         int role;
     };
     QList<Column> columns;
-
-signals:
-
-public slots:
-
 };
 
 #endif // CSVMODELWRITER_H