Add contributors of 5.2 5.3

doc/ack.xml

@@ -17,28 +17,36 @@ UMLGraph would not be in its current state without their contributions.
 <li>Nascif Abousalh-Neto</li>
 <li>Roger Alexander</li>
 <li>Panagiotis Astithas</li>
+<li>Bernd Blacha</li>
 <li>Yves Bossel</li>
 <li>Maxim Butov</li>
 <li>David P. Caldwell</li>
 <li>Anthony Callegaro</li>
+<li>Cimballi</li>
 <li>Dirk Datzert</li>
 <li>Christophe Deneux</li>
 <li>Nick Efthymiou</li>
 <li>Georgios Gousios</li>
 <li>Antti Hakala</li>
 <li>Art Hampton</li>
+<li>&#216;yvind Jergan</li>
 <li>Scott Johnson</li>
+<li>Gunho Kim</li>
+<li>Nikita Kozlov</li>
 <li>Trustin Lee</li>
 <li>Joshua Lim</li>
 <li>Vadim Nasardinov</li>
+<li>Laird Nelson</li>
 <li>S&#233;bastien Pierre</li>
 <li>Olek Poplavskyy</li>
 <li>Alessandro Riva</li>
 <li>Arnaud Rogues</li>
 <li>Jonathan R. Santos</li>
+<li>Jan Schl&#252;ter</li>
 <li>Sebastian Setzer</li>
 <li>J&#246;rn Guy S&#252;&#223;</li>
 <li>Andreas Studer</li>
+<li>Przemyslaw Szufel</li>
 <li>Ivan F. Villanueva B.</li>
 <li>Przemyslaw Wesolek</li>
 <li>Franz Wilhelmstoetter</li>