Forgot one dependency in the new external libs pom

moclodash/fr.inria.diverse.cloning.external-libs/pom.xml

@@ -85,6 +85,13 @@
                                         <version>1.6.6</version>
                                         <outputDirectory>lib</outputDirectory>
                                 </artifactItem>
+                                
+                                <artifactItem>
+	                                <groupId>org.slf4j</groupId>
+	                                <artifactId>slf4j-api</artifactId>
+	                                <version>1.7.6</version>
+	                                <outputDirectory>lib</outputDirectory>
+                                </artifactItem>
 								
 							</artifactItems>
 						</configuration>