ARTEMIS-1446 - Support Transformer configuration by properties

[michaelandrepearce]

Update Tranformer to be able to handle initiation via propertiers (map<string, string>)
Update Configuration to have more specific transfromer configuration type, and to take properties.
Support back compatibility.
Add AddHeadersTransformer which is a main use case, and can act as example also.
Update Control's to expose new property configuration
Add test cases
Update examples for new transformer config style

[michaelandrepearce]

Background small discussion on dev mail list http://activemq-dev.markmail.org/message/sunyg6rohsplus7e?q=properties+bridge suggesting to use properties (ala map<string,string>)

[jbertram]

This looks good, but I'm a bit concerned about using a Map in the management methods as this will preclude the use of tools like JVisualVM, JConsole, Jolokia, etc. to invoke those methods as they have no way to represent a Map in plain text. Perhaps consider using a comma delimited String of key=value pairs instead of Map for the management methods.

[michaelandrepearce]

@jbertram good point, i think the standard looking at other controls is to output JSON string form as well as map. Have updated so it returns/takes also a map as a JSON representation string.