v0.6.0

[0.6.0]

Changed

• Adjusted ignore settings in default settings file to ignore hidden
  directories, too.
• Properly handling pandoc's specs for YAML metadata, now. Metadata block now
  may also end with '---'.
• Reimplemented function to find updated files. Should be much faster now,
  when dealing with a large number of Zettels. Depending on UNIX tool find
  now, tested against GNU find.

Fixed

• With every run of zettels, the index was built from scratch. Now it only
  updates it if files in the Zettelkasten directory have changed.