Add support for SetHeader in WireTap introduced in Camel 2.8

The WireTap EIP in Camel runs in 2 modes

• tap existing messages
• create a new message and send it to the endpoint

The latter mode you could only construct a new message body using the XML DSL. If you need to provide headers you would have to use Java code in a org.apache.camel.Processor.
So based on customer feedback (MR-400) we have enhanced the XML DSL to allow to set headers as well.

So we should add support for that in Fuse IDE.

See wiretap wiki page for examples
http://camel.apache.org/wire-tap