Fix multiple listeners on command:beforeCommand event not stopping dispatch

[ChristopheMayet]

Hi Sacha,

I found a bug in the execution of events in this line of Script class.

Here the $this->_eventsManager->fire('command:beforeCommand', $command) call will return true (the last listener call) and then will not stop the command execution if multiple instance listn to this same event.

To reproduce :

• Define two event listeners attached to the event command
• Define beforeCommand method on both
• Return false on the first listener (with higher priority)
• Return true for the second listener
• Run a phalcon command

The execution is not stopped while one of listener returned false.

This PR adresses this issue.