Rework the intro

Tor Browser is not only a rebranded version of Firefox

wiki/src/doc/anonymous_internet/Tor_Browser.mdwn

@@ -2,10 +2,10 @@
 
 [[!img Tor_Browser/mozicon128.png link=no alt="Tor Browser icon"]]
 
-Tor Browser is a rebranded version of the [[Mozilla
-Firefox|http://www.mozilla.com/firefox/]] web browser. Given its popularity many
-of you have probably used it before and its user interface is like any other
-modern web browser.
+[Tor Browser](https://www.torproject.org/projects/torbrowser.html.en) is a web
+browser based on [Mozilla Firefox](http://getfirefox.com) and configured to
+protect your anonymity. Given the popularity of Firefox, you might have used it
+before and its user interface is like any other modern web browser.
 
 Here are a few things worth mentioning in the context of Tails.