vout: remove Thread and ThreadDisplay prefixes
Some static functions were named with prefixes. For unknown reasons,
there were two different prefixes (Thread
and ThreadDisplay
).
Their usage is confusing, because these functions could be called either
from Thread()
(the vout thread) or from another thread. For example,
vout_NextPicture()
is called from the decoder thread, and it calls
ThreadDisplayPicture()
, which itself calls many of the other prefixed
functions.
To avoid confusion (and for simplicity), remove these prefixes.