increase antlr to version 4.7 and active visitor

pom.xml

 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-  <modelVersion>4.0.0</modelVersion>
-
-  <groupId>edu.kit.formal</groupId>
-  <artifactId>ScriptParser</artifactId>
-  <version>1.0-SNAPSHOT</version>
-  <packaging>jar</packaging>
-
-  <name>ScriptParser</name>
-  <url>http://maven.apache.org</url>
-
-  <properties>
-    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <maven.compiler.target>1.8</maven.compiler.target>
-    <maven.compiler.source>1.8</maven.compiler.source>
-  </properties>
-
- <build>
-   <plugins>
-      <plugin>
-        <groupId>org.antlr</groupId>
-        <artifactId>antlr4-maven-plugin</artifactId>
-        <version>4.3</version>
-        <executions>
-          <execution>
-            <id>antlr</id>
-            <goals>
-              <goal>antlr4</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
-    </plugins>
- </build>
-
-  <dependencies>
-    <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
-      <version>4.12</version>
-      <scope>test</scope>
-    </dependency>
-    <dependency>
-      <groupId>org.antlr</groupId>
-      <artifactId>antlr4</artifactId>
-      <version>4.5</version>
-    </dependency>
-  </dependencies>
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>edu.kit.formal</groupId>
+    <artifactId>ScriptParser</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <name>ScriptParser</name>
+    <url>https://git.scc.kit.edu/sarah.grebing/ProofScriptParser</url>
+
+    <developers>
+        <developer>
+            <name>Sarah Grebing</name>
+            <organization>Karlruhe Institute of Technology</organization>
+        </developer>
+
+        <developer>
+            <name>Alexander Weigl</name>
+            <email>weigl@kit.edu</email>
+            <organization>Karlruhe Institute of Technology</organization>
+        </developer>
+    </developers>
+
+    <scm>
+    </scm>
+
+
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.target>1.8</maven.compiler.target>
+        <maven.compiler.source>1.8</maven.compiler.source>
+    </properties>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.antlr</groupId>
+                <artifactId>antlr4-maven-plugin</artifactId>
+                <version>4.7</version>
+                <executions>
+                    <execution>
+                        <id>antlr</id>
+                        <goals>
+                            <goal>antlr4</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <configuration>
+                    <visitor>true</visitor>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.antlr</groupId>
+            <artifactId>antlr4</artifactId>
+            <version>4.7</version>
+        </dependency>
+    </dependencies>
 </project>