Revert back TQt to Qt in the book title

Signed-off-by: Emanoil Kotsev <deloptes@gmail.com>

doc/html/guibooks.html

@@ -35,8 +35,8 @@ body { background: #ffffff; color: black; }
 <p> This is not a comprehensive list of books, there are many other
 books worth buying. Here we mention just a few GUI/UI books that don't
 gather dust in our shelves.
-<p> <b>C++ GUI Programming with TQt 3</b> by Jasmin Blanchette and Mark
-Summerfield, ISBN 0-13-124072-2. This is the Official TQt book written
+<p> <b>C++ GUI Programming with Qt 3</b> by Jasmin Blanchette and Mark
+Summerfield, ISBN 0-13-124072-2. This is the Official Qt 3 book written
 by two veteran Trolls.
 <a href="http://www.amazon.com/exec/obidos/ASIN/0131240722/trolltech/">(Read more about it or buy it.)</a>
 <p> <b>The Design of Everyday Things</b> by Donald Norman,