Fixed relation serialization of lemma as koral:token.

Change-Id: I1aaad693f34ea192653a260e7c8d69224c3645e9
diff --git a/pom.xml b/pom.xml
index 0d98b8f..7ad9bfe 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
 
 	<groupId>de.ids_mannheim.korap</groupId>
 	<artifactId>Koral</artifactId>
-	<version>0.27</version>
+	<version>0.28</version>
 	<packaging>jar</packaging>
 	<name>Koral</name>
 	<url>http://maven.apache.org</url>
@@ -138,6 +138,16 @@
 		<plugins>
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<version>2.20.1</version>
+				<configuration>
+					<excludes>
+						<exclude>**/OPINTest.java</exclude>
+					</excludes>
+				</configuration>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-compiler-plugin</artifactId>
 				<version>3.3</version>
 				<configuration>