Binary read support for length-prefixed containers

[zslayton]

• Lists - Add 1.1 binary reader support for length-prefixed Lists & S-Expressions #769
• S-expressions - Add 1.1 binary reader support for length-prefixed Lists & S-Expressions #769
• Structs
  • Symbol field encoding - Add 1.1 binary reader support for length-prefixed structs #768
  • FlexSym field encoding - Add 1.1 binary reader support for length-prefixed structs #768
• Follow-up to merge Symbol & FlexSym kinds. - Add 1.1 binary reader support for length-prefixed structs #768

[nirosys]

Need to follow-up with a PR to merge the separate struct kinds, and handle mid-struct encoding changes.