Use the pre-built jsPerf-specific Benchmark.js wrapper (#81)

https://github.com/jsperf/benchmark.js-wrapper
https://www.npmjs.com/package/@mathias/benchmark.js-wrapper-jsperf

Closes #64.

Author: mathiasbynens

npm-shrinkwrap.json

@@ -26,6 +26,7 @@
   },
   "homepage": "https://github.com/jsperf/jsperf.com",
   "dependencies": {
+    "@mathias/benchmark.js-wrapper-jsperf": "^1.0.0",
     "bell": "^3.0.0",
     "blipp": "^2.0.1",
     "boom": "^2.8.0",