sys/osxvideo/osxvideosink.*: Remove the event-loop-in-separate-thread modifications, because MacOSX is $#@(*%$# ! For...

Original commit message from CVS:
* sys/osxvideo/osxvideosink.h:
* sys/osxvideo/osxvideosink.m:
Remove the event-loop-in-separate-thread modifications, because MacOSX
is $#@(*%$# ! For those wondering, the event handling needs to be done
in the main thread after all..