Release Version 0.7.0

• API:
  • add Player.setProperty()
  • add VideoFrame class
  • add Player.onFrame() to get decoded frame, can be used by custom filters
  • support MediaStatus::Seeking
  • add snapshot MediaEvent
  • seek() callback parameter is -2 if seek request is ignored
• ABI: no break
• setBackgroundColor(): if alpha is 0(default), you have to call glClearColor(or d3d11 api) manually.
• Add FindMDK.cmake in sdk lib/cmake dir, support multiple target architectures.
• Fix multiple D3D11 renderer crash
• Fix crash if audio device is not available
• Fix music with cover buffering progress error
• Fix last frames not rendered if prepare() from a position closed to end of stream.
• Player.setVideoSurfaceSize(-1, -1) can remove the renderer
• prepare() starts from 0 if requested start position > stream duration or duration is unknown
• Improve A-B loop if B is closed to or larger than end of file
• Fix block if A-B loop restarts when previous seeking is not finished
• Music with cover art: fix png not rendered. fix block if stop by user.
• Seek:
  • Fix SeekFromNow
  • Fix audio file read error after seek
  • When end of stream decoded and in paused state
  • Fix seek never work if previous seek failed
  • position() never change after a seek error or a frequent seek request
• snapshot: fix msvc crash
• OpenGL:
  • Save and restore blend states
  • Skip loading EGL if context is not created by mdk
• FFmpeg:
  • support avfilter complex filters via Player property "video.avfilter" and "audio.avfilter"
  • Optimize audio filter if in/out parameters are the same
  • Improve video encoder
• VT decoder:
  • Fix the last frame not rendered
  • Support AnnexB streams
• Reduce exported classes
• Fix crashes, memory leaks in stress tests.
• Metal renderer: WIP
• Audio encoder: WIP