Emblem + addendums

[sgwilym]

• Added Earthstar emblem
• Added section on tag encodings
• Added addendum on friendly paths
• Removed restrictions on which bytes could appear in paths

[sgwilym]

Ah, I still need to a drawing of the Bao tree. @AljoschaMeyer can you send me a schematic for me to wobble-ise?

[AljoschaMeyer]

Not needed anymore.