use different integration test UI app which is open-jdk compatible

[toschneck]

Avoid this dependency:

<!-- JAVA FX - unfortunately only over this way possible yet -->
        <dependency>
            <groupId>javafx</groupId>
            <artifactId>jfxrt</artifactId>
            <version>${java.version}</version>
            <systemPath>${java.home}/lib/ext/jfxrt.jar</systemPath>
            <scope>system</scope>
        </dependency>

https://wiki.openjdk.java.net/display/OpenJFX/Main

[toschneck]

take a look together with #137