Implemented Coinfloor Module

Added Coinfloor module in response to issue #302.

Changes to XChange-Core:
>ExchangeSpecification:
>>Added field, getter and setter methods for cookie.

>BaseWebSocketExchangeService:
>>Added ability to keep WebSocket alive (sends pings every 15s)
>>Added methods to check WebSocket status (Connected, connecting, disconnected, etc...) - Used to support reconnectService
>>Moved interception of events by ReconnectService to WebSocketEventProducer

>ExchangeEventType
>>Added coinfloor specific events

>ExchangeStreamingConfiguration
>>Added getter method for keepAlive boolean

>ReconnectService
>>Now checks for current WebSocket status before reconnecting. Stops WebSocket from reconnecting on non-fatal errors.
>>ReconnectTask does the same thing. Stops WebSocket from reconnecting when WebSocket is still alive

>StreamingExchangeService
>>Updated annotations
>>Added interface method to retrieve WebSocket status

>WebSocketEventProducer
>>Moved interception of events by ReconnectService from BaseWebSocketExchangeService. Allows for more reliable interceptions, based on event receipt time, rather than event retrival time from queue.
>>Clarified connectionClosed logger debug string