0.6.33

Fixed

• The shared OTP root keeps one version of an app, not every version it has
  ever seen (MOB-143). The root is keyed by OTP hash rather than by project,
  so every app on the machine shares one lib/. Installing a dependency
  without removing its other versions left them side by side, and the code
  server resolves an application to the highest version it finds there.

  That splits an app in half. Its beams come from its own mix.lock and are
  pushed to the device; code:lib_dir/1 — and so code:priv_dir/1, which is
  where load_nif looks — resolves against the shared directory. An app
  locking exqlite 0.38.0 would load 0.38.0's beams and 0.40.0's
  sqlite3_nif.so, and on_load would fail with bad_lib, taking down every
  database connection and the boot with it. The visible error talked about
  database credentials and said nothing about a cached artifact.

  It was also non-local: an app that built fine yesterday broke because a
  different app upgraded a dependency. pythonx always swept by wildcard and
  never had this; exqlite, emlx and the generic installer removed only a
  malformed empty-version directory and let real versions accumulate.

  All four install paths now sweep other versions, keep the target, and log
  what they removed. A stale version left by an earlier build is cleaned on the
  next native build, so the first build after upgrading may report removals.