Add support for mapping between JBI NormalizedMessage attachments and Camel Message attachments

Following the discussion on CAMEL-385, the new attachment support in Camel 1.4 (currently unreleased) requires modification in the servicemix-camel component to allow a correct bidirectional mapping between attachments in JBI Normalized Messages and Camel Messages.

Attached to this issue there's a patch file with my implementation, tested with a simple flow from a file:poller (servicemix-file) to a ftp:sender (ftp:sender) connected one to the other through a camel route. The attachment test is done using BinaryFileMarshaler to send a binary file. Unfortunately no JUnit tests are provided as I was not able to understand the existing ones in the servicemix-camel component in order to add the attachment verification.

The patch requires:

• upgrading the Camel dependency to 1.4-SNAPSHOT (see SM-1347)

• upgrading the Spring dependency to 2.5.4 as used by Camel 1.4-SNAPSHOT (see SM-1346)

I hope it can be useful for anyone trying to pass JBI messages with attachments through a Camel route, and eventually be included in a future version of servicemix.