address_synchronizer fixes

is_mine: wallet expects get_address_index to work
imported wallets: history did not include addr keys after creation
deterministic wallets: get_addresses() should be sorted in derivation order

electrum/address_synchronizer.py

@@ -67,6 +67,10 @@ class AddressSynchronizer(PrintError):
         self.unverified_tx = defaultdict(int)
         # true when synchronized
         self.up_to_date = False
+
+        self.load_and_cleanup()
+
+    def load_and_cleanup(self):
         self.load_transactions()
         self.load_local_history()
         self.check_history()