plugin android: first draft:

- the plugin cancel its own import if it's not launched on Android platform
    - this plugin show a notification when a non MUC message is received when Cagou is not active
    - the device also optionally vibrate on notification

src/core/sat_main.py

@@ -177,6 +177,9 @@ class SAT(service.Service):
                 log.warning(u"Can't import plugin [{path}] because of an unavailale third party module:\n{msg}".format(
                     path=plugin_path, msg=e))
                 continue
+            except exceptions.CancelError as e:
+                log.info(u"Plugin [{path}] cancelled its own import: {msg}".format(path=plugin_path, msg=e))
+                continue
             except Exception as e:
                 import traceback
                 log.error(_(u"Can't import plugin [{path}]:\n{error}").format(path=plugin_path, error=traceback.format_exc()))