Another Cloud Ping

This is a follow up to the earlier AWSPing post. I just created a very similar http-based ping based on that, but with the following difference:

* Use JSON-P to avoid same-origin-policy request failures (this also fixed the Opera failures) * Repeat request 6 times (1 warmup + 5 measured) and display mean, median, min and max latency measurements * Allow ping against 40 different provides including 4 AWS regions