Minor - Add Costengineering.eu and agence-codecouleurs.fr to contributors

documentation/credits.html

@@ -700,11 +700,13 @@ These institutions and companies have either contributed to a better free Chamil
 <ul>
   <li>Académie d'Aix-Marseilles, France</li>
   <li>ACTA VZW, Belgium</li>
+  <li>agence-codecouleurs.fr, France</li>
   <li>APA e-Learning, Spain</li>
   <li>BeezNest Belgium, Brussels, Belgium</li>
   <li>BeezNest Latino, Lima, Peru</li>
   <li>Commission Scolaire des Hautes-Rivières, project TIC-FP, Canada</li>
   <li>Contidos Dixitais, Lugo, Spain</li>
+  <li>Costengineering.eu, The Netherlands</li>
   <li>Encora/HBO5, Antwerp, Belgium</li>
   <li>EPSU, Genève, Switzerland</li>
   <li>ESIAJ, Namur, Belgium</li>