EngineController prepareToPlay() call

[Alejandro Wainzinger]

So in an attempt to get MTP tracks playing directly off the device, I
added a call to Meta::Track->prepareToPlay() in the play(...) function
in the EngineController, but apparently that's only called when the
user chooses to play a particular song, not on track change.  I've
tried putting the call to this function all over the EngineController,
in the hopes that I could find the right place where I could allow for
gapless playback by loading the next track when the current one is
"aboutToFinish" but even in there it doesn't work right.  The thing
is, the copy operation takes just long enough that phonon concludes
that gapless playback is no longer possible, and stops playing.  Can
someone help me in the correct placement of this function call?