Now the core has a helper so that all the front ends don't need
to implement the scroll to show area API.
Now they simply have get and set scroll APIs.
This removes the global PDF_Password interface that had completely
bitrotted and moves it into the standard misc operation table with a
sensible defualt implementation.
This also cleans up and fixes the gtk frontend implementation of the
pdf password callback so it compiles.
Finally this moves the implementation to a sensible place alongside
the other exporters reducing target makefile complexity futher.
Currently it can only open, display and launch entries in an existing hotlist file.
TODO:
- Generate defualt hotlist when file not found.
- Add hotlist saving.
- Allow adding to hotlist.
- Allow hotlist editing.
- Allow hotlist nodes to be moved by dragging.
- Allow hotlist visit data to be updated.
