Support for WADL Doc text content when using @WADLDoc annotation in Resource class

Support for WADL was added in Wink 1.1.2 in Wink #313 (https://issues.apache.org/jira/browse/WINK-313).

It is stated that "You can document your resources, params, and request entities with @ WADLDoc to add some description."

However, after some tests and a quick peek at the source code, it seems that the @ WADLDoc annotation only takes one string parameter (value), and this string will end up in the "title" of the WADL Doc element, while the content of the Doc will remain empty and can't be assigned using annotations.

You can refer to line 768 of WADLGenerator.java, where there is no sign of the Doc content being set:

Doc getDocument(WADLDoc desc) {
        Doc d = new Doc();
        d.setTitle(desc.value());
        return d;
    }

This improvement could be implemented in (at least) two different ways:

1) Add one element to WADLDoc annotation (i.e. instead of only value(), have title() and content()).

2) Rename WADLDoc annotation to WADLDocTitle and create a new WADLDocContent annotation, each having a single value() element. Both annotations would be used to create the Doc object when generating WADL.

Doc content is supposed to be mixed content (i.e. it can hold some sub-elements) and my improvement request is only a half-baked implementation where only text content would be supported.

I could eventually work on a patch once the implementation details are specified if this improvement gets approved - still, changes should be pretty straightforward.