Add a method to get the connection mask

[elazar]

This is currently used in the client and the EventFilter, FeedTicker, and Bridge plugins.

[Renegade334]

NB that it's not used in EventFilter.

Also, it should be expressly stated that the connection mask should not be used as a key by which to store connection-specific data, as it can change during the session. Data keyed by connection should be stored as attached data in an SplObjectStorage instance.

[Renegade334]

On the subject of storing the event queue for each connection, what about creating an EventQueueFactoryAwareInterface? Would replace the need for examples like this.

Edit: phergie/phergie-irc-bot-react#19

[elazar]

Merged #6.