Add cmake helper script.
Add clang support.
Replace deprecated functions.
Fix deprecated names.
Update CMake package finding script.
Dirty fix C99 header in MSVC.
Fix TagLib problems.
Fix pkg-config issue.

Somehow pkg-config will omit default include path now.
Fix FindTagLib script.
Fix compile problem.
Merge branch 'develop' into ffmpeg
Fix messed demuxer.
Add padding to the end of stream.
Merge branch 'develop' into ffmpeg
Fix encoder for new API.
Fix tag encoding.
Take care of planar/planes sample.
Merge branch 'develop' into ffmpeg
Merge branch 'develop' into libav
Fix missing seek flag.