release version 0.3.1
This is a bug fix release
- fix user stop block
- fix some bugs at eof, e.g. unable to seek
- fix setLoop(0) can not disable looping
- support clang-cl 9.0
- c++ api: support g++ 4.9
- vaapi: sync surface after exporting drm handle
- improve ci. now nightly packages are uploaded automatically to https://sourceforge.net/projects/mdk-sdk/files/nightly
- now mdk can be installed via nuget in visual studio. https://www.nuget.org/packages/mdk