Adding system and config properties to Karaf via pax-exam-karaf

PaxExamKarafSysProps.java

    import static org.openengsb.labs.paxexam.karaf.options.KarafDistributionOption.editConfigurationFilePut;
    import static org.openengsb.labs.paxexam.karaf.options.KarafDistributionOption.editConfigurationFileExtend;      
    @Configuration
    public Option[] config() {
        return new Option[]{
                karafDistributionConfiguration(), keepRuntimeFolder(), logLevel(LogLevelOption.LogLevel.ERROR),
                editConfigurationFilePut("etc/system.properties", "mykey", "myvalue"),
                editConfigurationFileExtend("etc/config.properties", "org.osgi.framework.executionenvironment", "JavaSE-1.7")
        };
    }