remove testling since it seems to be abandoned and isn't functional

package.json

@@ -36,24 +36,6 @@
     "bench": "make bench",
     "test": "make test"
   },
-  "testling": {
-    "harness": "mocha-tdd",
-    "preprocess": "make test-browser",
-    "files": [
-      "test/_blank.js"
-    ],
-    "scripts": [
-      "node_modules/proclaim/lib/proclaim.js",
-      "node_modules/lodash/lodash.js",
-      "dist/6to5.js",
-      "dist/6to5-test.js"
-    ],
-    "browsers": [
-      "ie/8..latest",
-      "chrome/latest",
-      "firefox/latest"
-    ]
-  },
   "dependencies": {
     "ast-types": "0.5.0",
     "commander": "2.3.0",