do not raise exception if uri has an unknown key

gui/qt/main_window.py

@@ -779,7 +779,6 @@ class ElectrumWindow(QMainWindow):
         vbox.addWidget(pr_e)
         vbox.addLayout(Buttons(CopyCloseButton(pr_e.text, self.app, dialog)))
         dialog.setLayout(vbox)
-        #print len(data), data
         dialog.exec_()
 
     def export_payment_request(self, addr):

lib/util.py

@@ -261,8 +261,6 @@ def parse_URI(uri):
     for k, v in pq.items():
         if len(v)!=1:
             raise Exception('Duplicate Key', k)
-        if k not in ['amount', 'label', 'message', 'r', 'id', 'sig', 'timestamp', 'expiration']:
-            raise BaseException('Unknown key', k)
 
     out = {k: v[0] for k, v in pq.items()}
     if address: