GitLab

* modify processPacket to support fast seek

* add fastSeek to ProcessPacket decoder definition

* add fastseek flag to DecoderParametersStruct

* add fastseek flag to the process packet call

* no default params in C++ implementation

* enable flag in C++ implementation

* make order of parameters more normal

* register new seek with python api

* [somewhat broken] test suite for keyframes using pyav

* revert " changes

* add type annotations to init

* Adding tests

* linter

* Flake doesn't show up :|

* Change from unitest to pytest syntax

* add return type
Co-authored-by: Prabhat Roy <prabhatroy@fb.com>