Fixing a bug in the recording of zombie conflict resolutions

Dependencies

• [2] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).
• [3] CCLLB7OI Upgrading to Sanakirja 0.15 + version bump
• [4] UBCBQ5FG Removing pijul/src/commands/checkout.rs (unused file), as well as litorg comments

Change contents

• replacement in libpijul/src/diff/delete.rs at line 301
  [2.815274]→[2.815274:815340](∅→∅)
  − bytes_pos(lines_a, d[r].old).min(solved_conflict_end)
  [2.815274]

  [2.815340]
  + let pos = bytes_pos(lines_a, d[r].old) + bytes_len(lines_a, d[r].old, d[r].old_len);

  + pos.min(solved_conflict_end)
• replacement in libpijul/src/diff/delete.rs at line 305
  [2.815451]→[2.815451:815497](∅→∅)
  − if diff.pos_a[i].pos > next_pos {
  [2.815451]

  [2.815497]
  + if diff.pos_a[i].pos >= next_pos {
• replacement in libpijul/src/diff/delete.rs at line 309
  [2.815580]→[2.815580:815658](∅→∅)
  − || (i + 1 < diff.pos_a.len() && diff.pos_a[i + 1].pos <= pos)
  [2.815580]

  [2.815658]
  + || (i + 1 < diff.pos_a.len() && diff.pos_a[i + 1].pos < pos)