wallet: put Sync and Verifier in their own TaskGroup, and that into interface.group

electrum/gui/kivy/main_window.py

@@ -512,7 +512,7 @@ class ElectrumWindow(App):
 
     def on_wizard_complete(self, wizard, wallet):
         if wallet:  # wizard returned a wallet
-            wallet.start_threads(self.daemon.network)
+            wallet.start_network(self.daemon.network)
             self.daemon.add_wallet(wallet)
             self.load_wallet(wallet)
         elif not self.wallet:

electrum/gui/qt/__init__.py

@@ -236,7 +236,7 @@ class ElectrumGui:
 
             if not self.daemon.get_wallet(wallet.storage.path):
                 # wallet was not in memory
-                wallet.start_threads(self.daemon.network)
+                wallet.start_network(self.daemon.network)
                 self.daemon.add_wallet(wallet)
         try:
             for w in self.windows:

electrum/gui/stdio.py

@@ -34,7 +34,7 @@ class ElectrumGui:
         self.str_fee = ""
 
         self.wallet = Wallet(storage)
-        self.wallet.start_threads(self.network)
+        self.wallet.start_network(self.network)
         self.contacts = self.wallet.contacts
 
         self.network.register_callback(self.on_network, ['updated', 'banner'])

electrum/gui/text.py

@@ -30,7 +30,7 @@ class ElectrumGui:
             password = getpass.getpass('Password:', stream=None)
             storage.decrypt(password)
         self.wallet = Wallet(storage)
-        self.wallet.start_threads(self.network)
+        self.wallet.start_network(self.network)
         self.contacts = self.wallet.contacts
 
         locale.setlocale(locale.LC_ALL, '')