1f0038e Add support for the Ruby implementation of Bech32m (azuchi)

Pull request description:

ACKs for top commit:
  gwillen:
    sipa asked me to take a look at this, since I (more or less) know Ruby. I don't particularly know bech32[m], but I compared it to the reference Python implementation. Looks good to me! utACK 1f0038e .

Tree-SHA512: ee998541964f8e16167f24cf577e9554e427ead49848028c69829a7e30ca951aa14b7b31f469ce32ee9cc3e36d591e63ef403ea57dcda848249228fd69abc9ac