progress on BTC-related stuff.
BTC support
add a bitcoin dep
working through the btc proofs
refactor and consolidate
almost ready to fire it up
keybase btc actually working...
dedebug
plug into status
keybase id shows BTCs
bitcoyne update
iced-spawn update
keybase proofs update
factor out chainlinks
refactor of sig table construction
some stuff working
bugfixes
fix untracking
more tweaks and tests
version bump for keybase-proofs