Extend annotation processing framework to allow target aware processors and service (including base implementation)

Peter, can you please re-attach the patch, as I believe that there's missing code in the test case.

Eclipse messed with the patch file... which was good, because they didn't work properly anyway.
Now this is fixed.
Also: added ability of throwing a Mapping Exception if an Annotation is placed on a target where it should not be, instead of only returning false, which does not allow you to add further information about the reason of failure.

Thanks, Peter. Will look into this in the afternoon, once I am on my train towards snow ... .

Okay, just following up my own email from the afternoon: whilst I like the idea with the use of the MappingException, this does not work as intended. The class MappingException is part of the XML module, and the core module (where the Annotation* classes live) must not depend upon the XML module. I have tried to move the MappingException class to the core module (within the same package, as this class is part of the public API) ... but then I get sealing exceptions.

As such, I'd introduce a new Exception (MappingException, but local to the annotation processing package(s), and then (somewhere else) convert this to the XML MappingException. I hope I have expressed myslef clearly .. ,.

Ok. I introduced a new Exception within the annotation processing package, so this package is "stand alone".

Cheers, Peter