sout: sdi: replace the thread cleanup calls by a canceled boolean

mutex_cleanup_push() and vlc_cleanup_pop() are not available in C++. All we want is to tell the feeder thread to exit when it's idle.

The condition will be triggered when:

• a frame has completed
• the maxdelay to wait before scheduling a new frame has been reached
• the thread cancel has been requested

Also clean vlc_tick_t usage and allow win32 builds (untested, like the other platforms since we never build it)

Deprecates !306 (closed)