Sprite Frame Close External Editor Concurrent Modification Fix

Changes the cleanup loop which stops all of the external subimage
editors to remove the editors using an iterator first. This gets rid of
the concurrent modification exception when you have edited more than
one subimage at the time you save or close the frame. I chose to do it
this way because I didn't want to copy the entire collection. Later the
editors map could possibly be changed to a WeakHashMap which would
automatically remove the keys when the editors are no longer reachable
and eligible for garbage collection. It could also be changed to a
ConcurrentMap which would make it thread safe too.

org/lateralgm/main/LGM.java

@@ -132,7 +132,7 @@
 
 public final class LGM
 	{
-	public static final String version = "1.8.186"; //$NON-NLS-1$
+	public static final String version = "1.8.187"; //$NON-NLS-1$
 
 	// TODO: This list holds the class loader for any loaded plugins which should be
 	// cleaned up and closed when the application closes.

org/lateralgm/subframes/SpriteFrame.java

@@ -45,6 +45,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
@@ -1666,8 +1667,15 @@ public void dispose()
 	protected void cleanup()
 		{
 		if (editors != null)
-			for (ImageEditor ie : editors.values())
-				ie.stop();
+			// because stopping an editor removes it from the collection we must iterate
+			// here in a way that prevents concurrent modification exceptions by first 
+			// removing the editor through the iterator so that stop's remove is a noop
+			for (final Iterator<ImageEditor> it = editors.values().iterator(); it.hasNext();)
+				{
+				ImageEditor ie = it.next(); // << grab it first
+				it.remove(); // << remove it the safe way before stop does
+				ie.stop(); // << safe from concurrent modification now
+				}
 		}
 
 	public void lostOwnership(Clipboard arg0, Transferable arg1)