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/qvalidatedlineedit.h

@@ -9,6 +9,7 @@
 class QValidatedLineEdit : public QLineEdit
 {
     Q_OBJECT
+
 public:
     explicit QValidatedLineEdit(QWidget *parent = 0);
     void clear();