[mng] use additionalClasspathElements when running JUnit tests

Tests are running successful using mvn:test, but fail in eclipse, because m2eclipse doesn't put additionalClasspathElements on classpath, e.g.:
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<configuration>
<additionalClasspathElements>
<additionalClasspathElement>src/main/config</additionalClasspathElement>
</additionalClasspathElements>
</configuration>
</plugin>