ScriptLanguageIndex: use an ordered collection

The HashSet is not ordered, so iterating over it returns the
ScriptLanguages in a random order. But we want them in priority order,
which is the order they are added to the collection.

This change arguably breaks backwards compatibility, but in 99% of the
cases the API calls in practice will be the same (e.g., contains), so
I'm going to fudge this one.

Author: ctrueden

src/main/java/org/scijava/script/ScriptLanguageIndex.java

@@ -32,8 +32,8 @@
 package org.scijava.script;
 
 import java.io.File;
+import java.util.ArrayList;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 
@@ -48,7 +48,7 @@
  * @author Johannes Schindelin
  * @author Curtis Rueden
  */
-public class ScriptLanguageIndex extends HashSet<ScriptLanguage> {
+public class ScriptLanguageIndex extends ArrayList<ScriptLanguage> {
 
 	private static final long serialVersionUID = 1L;