* Add \since directive to each method.
* Add documentation for BScrollBar and BScrollView classes.
* Title Case group titles.
* Some other minor documentation updates.
Remove the reimplemented hook methods groups because some
hook methods are there, some are not, unfortunately doxygen can’t
tell if a hook method just calls the default or does something else and
we tend to include all the hook methods even if we don’t actually make
any functional changes to them making the docs a bit more verbose
than they otherwise would be.
