Refactor to use groups between network layers to make them less coupled and reusable:
link_frame (ethernet etc)
inet_packet (ipv4,ipv6 etc)
ip_packet (tcp packet (not stream), udp segment etc)
Rename data to payload as i think it makes more sense for network data
Move scalar into own package.
Split scalar code into decode related scalar code (that reads etc) and
scalar code that just transform the scalar value.
Use a scalar.Mapper interface instead of just a function.
Make mappers, assert and validat impement the interface.
