Updated KoralSpan. Added KoralException.

Change-Id: I0676a3ee17d8ecd2fb03b5a2044c11ac34e7a3b6
diff --git a/pom.xml b/pom.xml
index 28bfabf..692be5f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -20,6 +20,11 @@
     <dependency>
       <groupId>org.antlr</groupId>
       <artifactId>antlr4-runtime</artifactId>
+      <version>4.2</version>
+    </dependency>
+    <dependency>
+      <groupId>org.antlr</groupId>
+      <artifactId>antlr4-runtime</artifactId>
       <version>4.5.1</version>
     </dependency>
     <dependency>