add jets for luck:ed, sign-raw:ed, sign-raw-octs:ed, scad:ed, scas:ed, scap:ed

[newxiphiness]

• luck:ed and sign-(octs-)raw go together

  • luck:ed generates a public private keypair where the private keypair is generated from SHA512(seed) and the usual EdDSA clamping procedure is done on the first 32 bytes.
  • sign-(octs-)raw allows one to sign from a keypair generated with luck (or, from sca(d/s))

• scad, scas, scap allows one to 'tweak' a public/private keypair with a scalar

  • scad tweaks public and private
  • scas tweaks private
  • scap tweaks public