Slide­Show / Kiosk with auto advance and speed controls

This is based on https://apl.ninja/document/aruntalkstech/talking-slideshow-hrk6. I removed the talking bits and changed SetPage to AutoPage so that if you add/delete/change any slides you do not have to change the APL doc, just the datasource that you pass to it.

Also added speed controls and the ability to pause and resume the auto play

David Spiller and Meike helped develop this (any flaws go to me not them)