URL TS: Check whether a page with given URL exists

This is a simple class that can be used to check whether a page with a given URL exists.

The class establishes a connection to the server of the given URL and sends an HTTP HEAD request.

If successful the class can determine whether it returns the HTTP response code.

The code 200 means the page exists. The code of 404 means the page does not exist. The code 302 means the server is redirecting the request to another location.