Co-authored-by: Giacomo Zinetti <giacomo.zinetti@giko.it>

fix issue where auto-animate did not work when jumping three or more slides (i.e. longer than the view distance)

refactor hash parsing, fixes issue with autoplaying media not starting from internal links on mobile devices

new shortcuts; alt+arrow key skips fragments, shift+arrow key jumps to last slide in the given direction #1105

fixes #2635

The progress bar shows how many slides have been passed in total.
However, when clicking on the progress bar, the target slide is
computed among the subset of /horizontal/ slides.  Thus, when the new
slide is displayed, the progress bar has usually changed to a point
that is unrelated to the clicked one, which I find surprising.

With this change, the target slide is computed from the number of
total slides.  Thus, after a click on the progress bar, the resulting
progress is close to the clicked point, which seems more natural to
me.

There is a small typo in js/controllers/autoanimate.js.

Should read `transition` rather than `transiition`.