SEO Report: Get site SEO statistics from multiple sites

This class can get site SEO statistics from a given site and multiple other sites.

It can send HTTP requests to different sites to obtain statistics about a given site. Currently it can:

- Check if the specified site is responding
- Get the language and other meta tag data from the site home page
- Get the site incoming links and traffic rank from Alexa
- Get the number of site incoming links and pages indexed by Google
- Get the site trust ranking from WOT
- Get the site domain age since it was first registered
- Get the number of the Tweets of a site page
- Get the number of Facebook links of a site page
- Get the site Google Page Speed rank
- Get the site Google page rank