Make potential future instances of #8 easier to debug

With hostNum prepended to the address, the client won't even be
able to connect and will return an error message with the invalid
address.

Example:
    requests.exceptions.InvalidSchema: No connection adapters were found for '6http://localhost:27701/sync/meta'

README.md

@@ -61,7 +61,7 @@ create a file named `__init__.py` containing the code below and put it in
     import anki.sync, anki.hooks, aqt
 
     addr = "http://127.0.0.1:27701/" # put your server address here
-    anki.sync.SYNC_BASE = addr + "%s"
+    anki.sync.SYNC_BASE = "%s" + addr
     def resetHostNum():
         aqt.mw.pm.profile['hostNum'] = None
     anki.hooks.addHook("profileLoaded", resetHostNum)

addon/__init__.py

@@ -56,7 +56,7 @@ def updateui(self, state):
 
 def setserver():
 	aqt.mw.pm.profile['hostNum'] = None
-	anki.sync.SYNC_BASE = config['addr'] + "%s"
+	anki.sync.SYNC_BASE = "%s" + config['addr']
 
 addHook("profileLoaded", setserver)
 aqt.preferences.Preferences.__init__ = wrap(aqt.preferences.Preferences.__init__, addui, "after")