Advanced hit test refactor

Removed advanced hit testing because :
- it was called from within core package to platform while only applying to flash target.
- it was too complex and possibly buggy.
- it was a response to a rare corner case

Now, it can be re-implemented outside of cocktail if a project needs it, by adding a callback to the new onDocumentUpdate callback that will re-implement the code suppressed here. This callback can be added by inheriting from CocktailView