cinemaslides: Replace tmp-safe-link mechanism ...

[wolfgangw]

... with Ruby's fine builtin "shellwords". Duh.

Some kind of mechanism is required for filenames with spaces and non-ascii chars etc.

tmp-safe-link is buggy because, for example, sox/soxi will need correct filetype suffices which won't exist in a tmp-safe-link filename as it is now.

Wow, what an embarrassing f'up this tmp-safe-link thing was. Ripping it back out again will be a major pain, too, because I had made sure to embed the mechanism as deeply as possible. Heh. Suits me right.

Thanks to Andrae Steiner, who told me before, and to Ronan Delacroix who ran into it, took pity and reported back. You guys are of course awesome :)