Add Bakge Mesh File specification v1.0.0
spec/bmf-v1.0.0: Add data layout section title
spec/bmf-v1.0.0: Add format name string
spec/bmf-v1.0.0: Add NumVertices metadata field
spec/bmf-v1.0.0: Add Triangle struct and metadata
spec/bmf-v1.0.0: Add Normal and TexCoord data
spec/bmf-v1.0.0: Fix data layout section label
spec/bmf-v1.0.0: Syntax highlighting: C++
spec/bmf-v1.0.0: Fix missing semi-colon