Add inline allocation of bytes fields

This commit adds a new FT_INLINE allocation type that forces bytes
fields to be inlined into the struct. E.g., pb_byte_t my_bytes[32].
This requires max_size for the bytes field. The FT_INLINE type is
represented as a new LTYPE: FT_LTYPE_FIXED_LENGTH_BYTES.

This commit also updates the documentation with FT_INLINE and
FT_LTYPE_FIXED_LENGTH_BYTES.

Added an AUTHORS file in apparent order of appearance in the git log
history from $(git log --all).