fixes #43 - Exit status not reported back to caller

@@ -17,7 +17,8 @@ CASPER_ARGS.extend([os.path.join(CASPER_PATH, 'bin', 'bootstrap.js'), '--casper-
 CASPER_ARGS.extend(sys.argv[1:])
 
 try:
-    subprocess.call(CASPER_ARGS)
+    status = subprocess.call(CASPER_ARGS)
 except KeyboardInterrupt:
     print '\nCasperJS interrupted, exiting.'
-    sys.exit()
+    status = 0
+sys.exit(status)

@@ -467,7 +467,6 @@ var Tester = function(casper, options) {
             }
         }
         if (exit === true) {
-            console.log('exiting with status: ' + exitStatus);
             casper.exit(exitStatus);
         }
     };