stop_emission
Description:
Stops a signal's current emission.
This will prevent the default method from running, if the signal was g_signal_run_last and you connected normally (i.e. without the "after" flag).
Prints a warning if used on a signal which isn't being emitted.
Parameters:
| instance | the object whose signal handlers you wish to stop. | 
| signal_id | the signal identifier, as returned by lookup. | 
| detail | the detail which the signal was emitted with. |