Switch current layer away before removing a layer. We must switch current layer to another one before removing a layer group node. It avoids a crash since inkscape does not know the group node of the layer is removed, and it would emit a signal on this node later.

package org.madbutterfly;

import java.lang.Exception;

public class InvalidStateException extends Exception {
    public InvalidStateException() {
	super();
    }
    public InvalidStateException(String msg) {
	super(msg);
    }
}