Fix issue of add/remove a frame at a scene before all key frames of a layer. When you added or removed a frame at a scene before all key frames of a layer, frameline was not updated correctly. It seems nothing happened, but domview is updated. This changeset fix this issue by correcting logic for boundary case.

package org.madbutterfly;

import java.lang.Exception;

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