Release 2.2.0

Changed

• The default .rogoignore that the first --index writes now also lists
  dependency directories: node_modules/, bower_components/,
  jspm_packages/, .venv/, venv/, site-packages/, __pycache__/,
  .tox/ and .nox/. An existing .rogoignore is never rewritten; add the
  lines to it by hand.
• The chunker's token estimate counts digits, punctuation, whitespace runs
  and line breaks the way the tokenizer spends tokens on them, instead of a
  flat ~4.8 characters per token for Latin text. Tables, version lists,
  changelogs and data files tokenized at ~1-2 characters per token, so 11%
  of a notes vault's chunks and 3-6% of a node_modules tree and a
  virtualenv passed the model's 2,048-token context, and embed truncated
  them (the truncated N of M inputs warning). On the same corpora no chunk
  of the vault passes it now, and 5 of ~207,000 in the two dependency trees
  still do (tables of rare Unicode letters). Chunks get smaller in real
  tokens (the vault's average went from ~1,290 to ~860, about 1.5 times as
  many chunks for about the same tokens embedded).
• CHUNKER_VERSION is 3, so the next --index of an existing corpus
  rebuilds it once.