Release of [email protected] to npm

Changes

• Added minSendDelay option that slows down the rate at which a bot sends replies to the user. The default is 1 sec but can be set using an option passed to the bot. See TextBot.js unit test for an example of that.
• Added support to SlackBot for sending an isTyping indicator. This goes along with the message slow down.
• Added a new Message builder class to simplify returning messages with attachments. See the send-attachment.js test in TestBot for an example of using it.
• Added a new DialogAction.validatedPrompt() method to simplify creating custom prompts with validation logic. See basics-validatedPrompt example for a sample of how to use it.
• SlackBot didn't support returning image attachments so I added that and fixed a couple of other issues with the SlackBot.
• Updated the LKG build, unit tests, and package.json version.