Do not load the entire change in memory in log

Dependencies

• [2] SXEYMYF7 Fixing the bad changes in history (unfortunately, by rebooting).
• [3] PH7B6I3U Fixing log --hash-only
• [4] VO5OQW4W Removing anyhow in libpijul
• [5] WZVCLZKY address clippy lints
• [6] UNZXTNSJ Change text format: order dependencies in the order they were on the channel at record time
• [7] I52XSRUH Massive cleanup, and simplification

Change contents

• replacement in pijul/src/commands/log.rs at line 53
  [2.135819]→[2.135819:135873](∅→∅)
  − let change = changes.get_change(&h)?;
  [2.135819]

  [2.135873]
  + let header = changes.get_header(&h)?;
• replacement in pijul/src/commands/log.rs at line 55
  [2.135936]→[2.135936:136082](∅→∅)
  − writeln!(stdout, "Author: {:?}", change.header.authors)?;

  − writeln!(stdout, "Date: {}", change.header.timestamp)?;
  [2.135936]

  [2.136082]
  + writeln!(stdout, "Author: {:?}", header.authors)?;

  + writeln!(stdout, "Date: {}", header.timestamp)?;
• replacement in pijul/src/commands/log.rs at line 60
  [2.136197]→[2.136197:136269](∅→∅)
  − writeln!(stdout, "\n {}\n", change.header.message)?;
  [2.136197]

  [2.136269]
  + writeln!(stdout, "\n {}\n", header.message)?;
• replacement in pijul/src/commands/log.rs at line 62
  [2.136308]→[2.136308:136381](∅→∅)
  − if let Some(ref descr) = change.header.description {
  [2.136308]

  [2.136381]
  + if let Some(ref descr) = header.description {
• edit in libpijul/src/change.rs at line 137
  [2.834362]→[2.834362:834417](∅→∅)
  − // org id sKanuyTdfBvORra8t03TId+vXgcf/4TLpoyTdbWlSCw=
• edit in libpijul/src/change.rs at line 258
  [2.838210]→[2.838210:838265](∅→∅)
  − // org id RhbpWA5HDGKpilANJFPz8t1Ips9PJW+pBFkwmXNl21E=
• edit in libpijul/src/change.rs at line 325
  [2.840255]→[2.840255:840310](∅→∅)
  − // org id 11du9AL8hevTwTE48smNaTtU/x2O3eh4LYm6FPayeTw=
• replacement in libpijul/src/change.rs at line 384
  [2.842339]→[2.842339:842394](∅→∅)
  − // org id +Tmh0+vnf5AKRwS2S9/W5J9KUc2umjSBiLGrBg2vqXk=
  [2.842339]

  [2.842394]
  +
• edit in libpijul/src/change.rs at line 442
  [2.844728]→[2.844728:844783](∅→∅)
  − // org id t0CzNo3X9SFATJMMzCCew7o4s6KP6ZTxxBvpbZKrKe0=
• edit in libpijul/src/change.rs at line 684
  [2.852259]→[2.852259:852314](∅→∅)
  − // org id 4YhjVHcMd4xMYTDXLWLTMaiyiDHg8H/Hj/lt3t4f2eU=
• edit in libpijul/src/change.rs at line 917
  [2.860125]→[2.860125:860180](∅→∅)
  − // org id UyRvnSNfnjujP0ygPCmcfcQcIqtp5EjD3NGO3LXlt/0=
• replacement in libpijul/src/change.rs at line 1090
  [2.866604]→[2.866604:866659](∅→∅)
  − // org id j+CGohqSoJFz2ZtLqz9M7oC9UpfOWmyP7YWCbYjb+fI=
  [2.866604]

  [2.866659]
  +