Update HapVideoDRAFT.md

Proposed extension to allow the snappy data to be split up into smaller partitions, for separate decompression. Also allow for future potential options using a bit-mask. Discussion welcome, although I would like to move fast on this since I need it for a project.
Update HapVideoDRAFT.md

Re-written as per discussion
Update HapVideoDRAFT.md

Updated with notes from Tom
Update HapVideoDRAFT.md

Updated as per discussions with Tom. Hope I got everything correct.
Fix typo
Describe frame header as section header, clarify section size excludes section header, other edits. Does not change frame layout
Decode support for chunked Hap in souce files
Merge branch 'chunks'