Exchange rate plugin fixes for multiple windows

This should be enough to keep everything working that was working
before.  The plugin itself needs a lot more work to fix existing
bugs and be sane.

gui/qt/__init__.py

@@ -201,6 +201,7 @@ class ElectrumGui:
             self.start_new_window(self.config, full_path)
 
     def new_window(self, path):
+        # Use a signal as can be called from daemon thread
         self.app.emit(SIGNAL('new_window'), self.config, path)
 
     def start_new_window(self, config, path=None):
@@ -215,6 +216,7 @@ class ElectrumGui:
             if not wallet:
                 return
             w = ElectrumWindow(config, self.network, self)
+            run_hook('new_window', w)
             w.connect_slots(self.timer)
 
             # load new wallet in gui

gui/qt/history_widget.py

@@ -76,7 +76,7 @@ class HistoryWidget(MyTreeWidget):
             self.insertTopLevelItem(0, item)
             if current_tx == tx_hash:
                 self.setCurrentItem(item)
-        run_hook('history_tab_update')
+        run_hook('history_tab_update', self.parent)
 
     def update_item(self, tx_hash, conf, timestamp):
         icon, time_str = self.get_icon(conf, timestamp)

gui/qt/main_window.py

@@ -1395,7 +1395,7 @@ class ElectrumWindow(QMainWindow):
             e.setFrozen(False)
         self.set_pay_from([])
         self.update_status()
-        run_hook('do_clear')
+        run_hook('do_clear', self)
 
     def set_frozen_state(self, addrs, freeze):
         self.wallet.set_frozen_state(addrs, freeze)