input: No need to signal input's end to the playlist now that the playlist gets an event for that one.

(To better track when to attach/detach events).

Currently libvlc uses "state" callback to notice input state changes, and the playlist notice input state change via direct call from the input.
playlist can't use the "state" variable as it is also used by the playlist to ask the input to do a certain action.

The event approach is much more clear here.

Add comment about getVariable() and setVariable() JS function: they are removed because of their security implications. Everyone is advice to use the newer ActiveX v2 (IVLCControl2) interface instead.

- VLCControl::setVariable()
- VLCControl::getVariable()
- VLCControl::get_PlaylistIndex()

This reverts commit 722f244d.

This reverts commit 097f8fc9.

I'm not sure why we have a PRODUCT_VERSION and VERSION

This is a bit contriversial, but libvlc actually uses vlc://nop, and this without a playlist.