backend, frontends: callbacks refactoring:

- launchAction is now async, and return a dictionary for its result
    - no more action_id, actionResult* are deprecated
    - callback system is about to be unified

src/memory/memory.py

@@ -212,7 +212,7 @@ class Params(object):
         self.default_profile = None
         self.params = {}
         self.params_gen = {}
-        host.registerGeneralCB("registerNewAccount", host.registerNewAccountCB)
+        host.registerCallback(host.registerNewAccountCB, force_id="registerNewAccount")
 
     def createProfile(self, profile):
         """Create a new profile