[osx] - add function for identifying osx snow leopard runtime
[settings] - add settingscondition OsxIsSnowLeopard
[osx/settings] - make the fake fullscreen option only visible when running
on snowleopard - it leads to black screen on all later osx versions
[AE/osxsink] - don't set the altered outputformat which might have wrong
channel count
Merge pull request #4894 from Memphiz/osxfakefullscreen

[osx] - only show the fake fullscreen option on snow leopard
Merge pull request #4899 from Memphiz/osxsinkphysicalformat

[AE/osxsink] - don't set the altered outputformat which might have wrong channel count
videoplayer: adapt lateness detection and dropping to buffering
video player: present correct pts to user for a/v sync (after buffering in renderer)
videoplayer: some rework and documentation
renderer: bump buffers to 5
videoplayer: update frametime, it might change due to fps detection
videoplayer: give streams with invalid fps a chance for fps detection
dvdplayer: allow rewinding at end of stream, do a seek after rewind
dvdplayer: observe pts counter overflow
dvdplayer: avoid short screen flicker caused by unnecessary reconfigure of renderer
vdpau: advanced settings for auto deinterlacing
player: fix rewind
OMXPlayer: some caching fixes for pvr
fix incorrect display of fps when dr kicks in
renderer: allow some lateness within vblank interval