Catch exceptions on arpmonitor

Fixes #119

examples/arpmonitor.cpp

@@ -92,9 +92,14 @@ int main(int argc, char *argv[])
     config.set_promisc_mode(true);
     config.set_filter("arp");
 
+    try {
         // Sniff on the provided interface in promiscuous mode
         Sniffer sniffer(argv[1], config);
         
         // Only capture arp packets
         monitor.run(sniffer);
+    }
+    catch (std::exception& ex) {
+        std::cerr << "Error: " << ex.what() << std::endl;
+    }
 }