Enable SIGINT handler

You could try/catch around this, and if the exception is AbortException you silence it otherwise you let it bubble up? That would probably require a `Symfony\Component\Debug\Debug::enable(-1)` in the app if it's not there to convert everything to exceptions. Not sure if the curl exception would come before the AbortException though that could be a problem and require to set a flag when the signal is caught instead of just throwing.