Qt5 compatibility

This commit squashes all the changes in the Qt5 branch
relative to master.

Backward compatibility with Qt4 is retained.

Original authors:

- Philip Kaufmann <phil.kaufmann@t-online.de>
- Jonas Schnelli <jonas.schnelli@include7.ch>

src/qt/transactionview.cpp

@@ -176,7 +176,11 @@ void TransactionView::setModel(WalletModel *model)
         transactionView->horizontalHeader()->resizeSection(TransactionTableModel::Status, 23);
         transactionView->horizontalHeader()->resizeSection(TransactionTableModel::Date, 120);
         transactionView->horizontalHeader()->resizeSection(TransactionTableModel::Type, 120);
+#if QT_VERSION < 0x050000
         transactionView->horizontalHeader()->setResizeMode(TransactionTableModel::ToAddress, QHeaderView::Stretch);
+#else
+        transactionView->horizontalHeader()->setSectionResizeMode(TransactionTableModel::ToAddress, QHeaderView::Stretch);
+#endif
         transactionView->horizontalHeader()->resizeSection(TransactionTableModel::Amount, 100);
     }
 }