Command pagetest fetches provided url and all linked resources, printing
diagnostic timings.

pagetest first fetches html page at given url, then parses html, extracting
urls from <link>, <script>, <img> tag attributes, then issues HEAD requests
to these urls and reports timings and response codes for all requests done.

On certain requests for the same domain some of the reported timings may be
zero, this is a result of connection reuse.