added sonarcloud support (hopefully it works)

.travis.yml

@@ -3,3 +3,8 @@ dist: trusty
 language: java
 before_install:
   - echo "MAVEN_OPTS='-Xmx2g'" > ~/.mavenrc
+addons:
+  sonarcloud:
+    organization: "magefree"
+script:
+   - mvn clean org.jacoco:jacoco-maven-plugin:prepare-agent install sonar:sonar

sonar-project.properties

@@ -0,0 +1,2 @@
+sonar.projectName=XMage
+sonar.projectVersion=1.4.332V0