Uncaught errors when killing child process

[tlhunter]

Hitting Ctrl+C can sometimes cause uncaught errors to be throw. We should instead catch and emit.

[   FATAL] Got some major errors from our scan command:Error: Command failed:    

/home/tlhunter/Projects/node-wireless-test/node_modules/wireless/index.js:337    
            throw err;                                                           
                  ^                                                              
Error: Command failed:                                                           
    at ChildProcess.exithandler (child_process.js:647:15)                        
    at ChildProcess.emit (events.js:98:17)                                       
    at maybeClose (child_process.js:755:16)                                      
    at Socket.<anonymous> (child_process.js:968:11)                              
    at Socket.emit (events.js:95:17)                                             
    at Pipe.close (net.js:465:12)