De-linkify domain reference to avoid spurious link check failure

The license information readme contains a reference to www.arduino.cc. 

Text that looks like a domain is automatically linkified by common Markdown renderers (including the one used by GitHub for repository contents), converting this to a link to http://www.arduino.cc. The project infrastructure includes a check for broken links in the Markdown files. The markdown-link-check tool that provides this check is smart enough to also check these auto-linkified links.

When the http://www.arduino.cc URL is opened normally, the Arduino website simply redirects to https://www.arduino.cc (note the https scheme) and all is well. However, apparently due to some draconian security settings on the arduino.cc web infrastructure, when markdown-link-check attempts to load that URL, it fails spuriously with an HTTP 403 Forbidden response code.

This could be fixed by changing the `www.arduino.cc` text to something like `[www.arduino.cc](https://www.arduino.cc)`. However, I don't think there was ever an intention to encourage  the reader of the text to visit that domain. Rather, it was added as an alternative way of identifying the entity referred to as "ARDUINO SA". For this reason, I think the most appropriate solution to the spurious link check failure is to prevent the linkification of this text. This is done by injecting HTML comment tags at strategic locations. These tags cause the text to no longer be recognized as a domain name by the auto-linkifying code of the markdown-link-check tool and the GitHub Flavored Markdown renderer both.

Author: per1234

README.md

@@ -240,7 +240,7 @@ e-mail contact: security@arduino.cc
 
 ## License
 
-Copyright (c) 2018 ARDUINO SA (www.arduino.cc)
+Copyright (c) 2018 ARDUINO SA (www<!---->.arduino<!---->.cc)
 
 The software is released under the GNU General Public License, which covers the main body
 of the serial-discovery code. The terms of this license can be found at: