Safer close, heartbeat

Delivery mode - persistent

sendMessage split into sendMessage and sendMessageId
sendMessageToQueue split into sendMessageToQueue and sendMessageToQueueId

Because of an overload bug in 2019.1.0

Added isOpen method

Always allow Content-Type

Catch null exchange value

New optional exchange parameter

Fix for UTF8 Windows errors

Test java class

Added optional message properties: correlationId, messageId

For #1

Better stream handing