No useless wake up and simplify.
Fix a few race conditions with deactivation.

(Moved around playlist code)

No functionnality changes.

Some interfaces may assert because of missing playlist lock.

As discussed on IRC. Yield was quite confusing.

Fabio Ritrovato authored Aug 14, 2008 and hartman committed Aug 14, 2008

Signed-off-by: Derk-Jan Hartman <hartman@videolan.org>

playlist: Use PL_LOCK_IF and PL_UNLOCK_IF to perform some more checks on lock state. And fix a unlocked usage of get_current_status_item().

That may fix or help to fix some input item leaks.

This allows using pl_Yield() from video outputs and friends, on
condition that pl_Yield() return value be checked for NULLity.

Should fix #1667.

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