Improved AnnotationTag API and refactored some uses

Minor updating of AnnotationTag and its uses.

* Deprecates getting the number of tags and getting a specific element
* Added a return for the collection of elements
* Added constructors
* Updated client code to use the collection of elements and the new constructors

Ran the soot tests, but most of them were failing before and after - so that doesn't help knowing if anything got broken.