Fixed py2 problems and other improvements

We've changed the way plugins are activated, and removed the notion of
deactivated plugins.
Now plugins activate asynchronously.
When calling a plugin, it will be activated if it wasn't, and the call will wait
for the plugin to be fully activated.

senpy/blueprints.py

@@ -89,6 +89,7 @@ def basic_api(f):
             response = f(*args, **kwargs)
         except Error as ex:
             response = ex
+            response.parameters = params
             logger.error(ex)
             if current_app.debug:
                 raise