Also fix voice message mark as read when autoplaying after previous.
Also show play icon and don't show playlist for audio files that do
not have shared music files attributes but have audio file mime type.
That way audio files and voice/video messages will play in context
(one after another with ability to go to next or previous in player)
almost always, no matter at what part of message history we are.
Media::Player::Widget displays the current voice / video message
if it is played and the current song otherwise.
It is created when a voice / video message starts and is destroyed
when all the voice / video messages in the playlist are finished.
Use AudioMsgId instead of videoPlayId.
Any audio track now can be a child loader track of some video clip.
Use Type::Voice instead of Type::Video for round video messages.
Video messages play / pause / resume the same way as voice messages.
Currently the build without implicitly included precompiled header
is not supported anyway (because Qt MOC source files do not include
stdafx.h, they include plain headers).
So when we decide to support building without implicitly included
precompiled headers we'll have to fix all the headers anyway.
