Source locations for java doc

Currently, source locations for java doc are not included in IJavaElements generated from the Groovy compiler. This is because java doc locations are ignored by the parser. The problem is that this is preventing source hovers from displayingthe JavaDoc contents of the item being hovered on.

I can see several possible ways of adding Javadoc:

1. Enhance the groovy parser with a new grammar and new AST elements that represent the JavaDoc.

2. After a reconcile do a second walk of the file and determine the start and end points of all JavaDoc comments.

#1 is a much better solution, but would require a fairly significant patch to the compiler. There has been some talk of doing this on the mailing list, but I do not think any progress has been made (certainly, there are no JIRAs for it). #2 would work for the plugin. However, I am a little concerned about the extra time it might take during a reconcile.