Improving unrecord performance (8 times faster on my tests)

Dependencies

• [2] I24UEJQL Various post-fire fixes
• [3] T7CAACFB Fixing zombie conflicts (some vertices were wrongly detected alive)
• [4] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).
• [5] 6YMDOZIB Refactoring apply
• [6] YN63NUZO Sanakirja 1.0
• [7] VO5OQW4W Removing anyhow in libpijul
• [8] CCLLB7OI Upgrading to Sanakirja 0.15 + version bump

Change contents

• replacement in libpijul/src/find_alive.rs at line 52
  [2.85366]→[4.134828:134912](∅→∅),[4.765422]→[4.134828:134912](∅→∅)
  − let mut stack = vec![SerializedEdge::empty(vertex0.end_pos(), ChangeId::ROOT)];
  [2.85366]

  [2.85367]
  + let mut stack = vec![(SerializedEdge::empty(vertex0.end_pos(), ChangeId::ROOT), false)];
• replacement in libpijul/src/find_alive.rs at line 54
  [2.85409]→[4.765697:765737](∅→∅),[4.765697]→[4.765697:765737](∅→∅)
  − while let Some(elt) = stack.pop() {
  [2.85409]

  [4.134913]
  +

  + // `to_self` tells whether we've already marked a vertex alive

  + // along the path from `vertex0`. This can happen if the only

  + // vertices alive are from change `change`.

  + while let Some((elt, mut to_self)) = stack.pop() {
• edit in libpijul/src/find_alive.rs at line 92
  [3.69]→[4.767403:767445](∅→∅),[4.767403]→[4.767403:767445](∅→∅)
  − alive.insert(vertex);
• edit in libpijul/src/find_alive.rs at line 93
  [4.135438]

  [4.16362]
  + alive.insert(vertex);
• edit in libpijul/src/find_alive.rs at line 96
  [4.16444]

  [4.16444]
  + } else if !to_self {

  + alive.insert(vertex);

  + to_self = true;
• replacement in libpijul/src/find_alive.rs at line 109
  [4.768674]→[4.135478:135509](∅→∅)
  − stack.push(*v)
  [4.768674]

  [4.768704]
  + stack.push((*v, to_self))