v0.0.4

• update getText() method. Now it returns Optional. This is reduce the code when processing cases when the message is not text.
• add Bot's constructor without BotHandler object. This makes it easier to initiate the bot. If you do not want to process webhooks about instance state or device status, simply do not specify BotHandler in the constructor, the default handler will be used, which ignores these types of hooks.
• Start Scene object removed from bot's constructor. Now you should use setter setStartScene() for edit startScene. Default value is null.
• README and examples updated