INT-2126 Add TcpConnection Event Publisher

Reference: https://jira.springsource.org/browse/INT-2126

* Add TcpConnectionEvent for OPEN, CLOSE, EXCEPTION.
* Add Event Type Enum - Provides type safety for event types.
* Add <int-ip:tcp-connection-event-inbound-channel-adapter />
* Add the ability to filter events (restrict to one or more subclasses)
* Add publishEvent() to TcpConnectionSupport to permit, for example, connection interceptors to publish events via the connection, but the event source can only be the connection used to publish the event.
* Add documentation to Reference Documentation section *What's New*

INT-2871 Provide Mechanism to Find TCP Connections
Reference: https://jira.springsource.org/browse/INT-2871

* Add getOpenConnectionIds() to Abstract Connection Factory
* Add closeConnection(String connectionID)
* Introduce removeClosedConnectionsAndReturnOpenConnectionIds

INT-2877 TCP Extension Improvements
Reference: https://jira.springsource.org/browse/INT-2877

* Make improvements to make extension easier.
* Add setCustomHeaders() to mapper.
* Add mapper to connection factory namespace parser.
* Add plumbing for stateful Deserializers.
* Refactor setting standard headers
* rename setCustomHeaders to supplyCustomHeaders - returning a Map and not exposing the MessageBuilder to subclasses

INT-2872 Remove Deprecated Items in ip Module
Reference: https://jira.springsource.org/browse/INT-2872

* pool-size Attribute
* setScheduler
* TcpSendingMessageHandler.getConnection()
* Deprecated attribute on TCP Connection Factory.
Merge pull request #743 from garyrussell/INT-2877

* garyrussell-INT-2877:
  INT-2126 Add TcpConnection Event Publisher