v0.0.9 - 2014/01/21 - Added top-down link checking.
                      Non-normative items with a zero-ended level are now headings.
                      Added a CSS for generated HTML.
                      The 'publish' command now accepts an output file path.

v0.0.8 - 2014/01/16 - Searching for 'ref' will now also find filenames.
                      Item files can now contain arbitrary fields.
                      Document prefixes can now contain numbers, dashes, and periods.
                      Added a 'normative' attribute to the Item class.

v0.0.7 - 2013/12/09 - Always showing 'ref' in items.
                      Reloading item attributes after a save.
                      Inserting lines breaks after sentences in item 'text'.

v0.0.6 - 2013/12/04 - Added basic report creation via 'doorstop publish'.

v0.0.5 - 2013/11/20 - Added item link and reference validation.
                      Added cached of loaded items.
                      Added preliminary VCS support for Git and Veracity.

v0.0.4 - 2013/11/04 - Implemented 'add', 'remove', 'link', and 'unlink' commands.
                      Added basic document tree validation.

v0.0.3 - 2013/10/17 - Added the initial Document class.
                      Items can now be ordered by 'level' in a Document.
                      Initial tutorial created.

v0.0.2 - 2013/09/25 - Changed 'doorstop init' to 'doorstop new'.
                      Added the initial Item class.
                      Added stubs for the Document class.

v0.0.1 - 2013/09/11 - Initial release of Doorstop.
