Added a function to create an avif image from a set of frames

Renamed Flag to match ffmpegs name

Automatic rescaling to stream time base when writing packet.

Namespace for IAVPointer renamed

Added static convert to convert two frames

BugFix, IOContext not seekable

Ranamed Interface/abstract base class

Added Interface IAVPointer<T> which has a T* Pointer property. Most FFmpeg-Classes implement this explicitly.

Remove/RemoveAt/RemoveById added

MuxerContext, Example, Write/ReadFrame depri, Update ToC

SeekExactly

ReadPacket renamed

Renamed Read/WriteFrame to Read/WritePacket

res->id = res->index;

BugFix muxer: AddStream now sets the streams id to its index.