Bitcoin-Qt: add "send coins" to context menu in addressbook

- allows to directly select an address from the addressbook, chose "send
  coins" from the context menu, which sends you to sendcoins tab and fills
  in the selected address

src/qt/addressbookpage.h

@@ -68,6 +68,8 @@ private slots:
     void on_signMessage_clicked();
     /** Open the verify message tab in the Sign/Verify Message dialog with currently selected address */
     void on_verifyMessage_clicked();
+    /** Open send coins dialog for currently selected address (no button) */
+    void onSendCoins_clicked();
     /** Generate a QR Code from the currently selected address */
     void on_showQRCode_clicked();
     /** Copy label of currently selected address entry to clipboard (no button) */
@@ -85,6 +87,7 @@ private slots:
 signals:
     void signMessage(QString addr);
     void verifyMessage(QString addr);
+    void sendCoins(QString addr);
 };
 
 #endif // ADDRESSBOOKPAGE_H