Public keys are not compact/pretty

[jameshaydon]

It would be nice to have a nice representation of public keys since these will probably be used as user IDs. Unfortunately right now they look like this:

[:PublicKey
 {:public_curve [:CurveFP
  [:CurvePrime
  1.15792089237316195423570985008687907853269984665640564039457584007908834671663e77
  [:CurveCommon
  {:ecc_a 0.0
   :ecc_b 7.0
   :ecc_g [:Point
   5.506626302227734366957871889516853432625060345377759417550018736038911672924e76
   3.2670510020758816978083085130507043184471273380659243275938904335757337482424e76]
   :ecc_h 1.0
   :ecc_n 1.15792089237316195423570985008687907852837564279074904382605163141518161494337e77}]]]
  :public_q [:Point
  1.11054692487265016800292649812157504820937148585989526304621614094061257232989e77
  3.6059272479591624612420581719526072934261866833779446725219340058438651734523e76]}]

[jameshaydon]

It would be great to choose a canonical format not associated with Generic encoding of Haskell types, since we already want to change this.