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/walletmodel.h

@@ -26,6 +26,7 @@ public:
 class WalletModel : public QObject
 {
     Q_OBJECT
+
 public:
     explicit WalletModel(CWallet *wallet, OptionsModel *optionsModel, QObject *parent = 0);
     ~WalletModel();
@@ -161,5 +162,4 @@ public slots:
     void pollBalanceChanged();
 };
 
-
 #endif // WALLETMODEL_H