CLN: Simplify API logic.
WIP: Start work on better API. Video works. TiffStack has standin code.
TST: Update tests. Replace bw ref. frames with color.
REF: Decode the video into a tempfile.
REF: FFmpegVideoReader is a FramesSequence

Parse ffmpeg stderr in same pass.
Merge pull request #1 from danielballan/api

Api + ffmpeg re-write