Execute tests in Travis

Use explicit "mvn verify", instead of implicit "mvn test" which Travis executes by default, because tycho-surefire-plugin:test is bound to integration-test phase.

Author: Godin

.travis.yml

@@ -1 +1,9 @@
 language: java
+
+# Skip "install" stage:
+install: true
+
+# Use container-based infrastructure:
+sudo: false
+
+script: mvn -V -B -e verify