Update Groovy to version 2.5.22 for compatibility with Java 9 and newer

build.gradle

@@ -57,7 +57,7 @@ project(":de.bmotionstudio.gef.editor") {
 		// hardcode a specific MXParser version here.
 		// It *should* be safe to update this when a new version is released.
 		implementation group: "io.github.x-stream", name: "mxparser", version: "1.2.2"
-		implementation group: "org.codehaus.groovy", name: "groovy", version: "2.0.5"
+		implementation group: "org.codehaus.groovy", name: "groovy", version: "2.5.22"
 	}
 }
 

de.bmotionstudio.gef.editor/.classpath

@@ -4,13 +4,7 @@
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="src" path="src"/>
 	<classpathentry kind="output" path="bin"/>
-	<classpathentry exported="true" kind="lib" path="lib/dependencies/antlr-2.7.7.jar"/>
-	<classpathentry exported="true" kind="lib" path="lib/dependencies/asm-4.0.jar"/>
-	<classpathentry exported="true" kind="lib" path="lib/dependencies/asm-analysis-4.0.jar"/>
-	<classpathentry exported="true" kind="lib" path="lib/dependencies/asm-commons-4.0.jar"/>
-	<classpathentry exported="true" kind="lib" path="lib/dependencies/asm-tree-4.0.jar"/>
-	<classpathentry exported="true" kind="lib" path="lib/dependencies/asm-util-4.0.jar"/>
-	<classpathentry exported="true" kind="lib" path="lib/dependencies/groovy-2.0.5.jar"/>
+	<classpathentry exported="true" kind="lib" path="lib/dependencies/groovy-2.5.22.jar"/>
 	<classpathentry exported="true" kind="lib" path="lib/dependencies/mxparser-1.2.2.jar"/>
 	<classpathentry exported="true" kind="lib" path="lib/dependencies/xmlpull-1.1.3.1.jar"/>
 	<classpathentry exported="true" kind="lib" path="lib/dependencies/xstream-1.4.20.jar"/>

de.bmotionstudio.gef.editor/META-INF/MANIFEST.MF

@@ -149,13 +149,7 @@ Export-Package: de.bmotionstudio.gef.editor;
    org.eclipse.swt.widgets,
    de.bmotionstudio.gef.editor"
 Bundle-ClassPath: .,
- lib/dependencies/antlr-2.7.7.jar,
- lib/dependencies/asm-4.0.jar,
- lib/dependencies/asm-analysis-4.0.jar,
- lib/dependencies/asm-commons-4.0.jar,
- lib/dependencies/asm-tree-4.0.jar,
- lib/dependencies/asm-util-4.0.jar,
- lib/dependencies/groovy-2.0.5.jar,
+ lib/dependencies/groovy-2.5.22.jar,
  lib/dependencies/mxparser-1.2.2.jar,
  lib/dependencies/xmlpull-1.1.3.1.jar,
  lib/dependencies/xstream-1.4.20.jar