Digger v2.4 (2015-10-05)

• Fetch tags explicitly when updating
  (fixes some "unknown /ambiguous revision" errors)
• Prepend result bin directory to PATH
  (fixes behavior when a dmd binary was installed in /usr/bin)
• Add support for the debugDMD build option on POSIX
• Fix incorrect repository tree order when using git cache engine
• Fix rebuild ignoring build options on the command-line
• Automatically install KindleGen locally when building website
• Update OptLink installer
• Download platform-specific DMD release packages
  (contributed by Martin Nowak)