Looking for things to hack on?  Great, here's a partial list:

* Wean off openssl's -lcrypto: use libsodium for all RNG, gmp for base58.
* Grep for FIXME and fix one :)
* Look on https://github.com/ElementsProject/lightning/issues
* Write canned input/output test cases for various conversations, and
  include them in a form suitable for other implementations to test.