Transitioning Unix installs to the XDG Base Directory Specification
===================================================================

Currently, Bazaar stores its configuration files and plugins under the
directory ~/.bazaar on unix installs.  On Windows, this is
%APPDATA%/Bazaar/2.0 and on Mac OS X, the directory is ~/.bazaar.  With the
XDG Base Directory specification
(http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html), many
Linux and Unix platforms have tried to centralize configuration files under a
specific directory referred to as $XDG_CONFIG_HOME.  This has a default value
of ~/.config.

Bazaar would like to be a good Unix citizen by using these standard locations
for configuration files.  As such, we should support that location, but not
require it.  Note that the following descriptions do not apply
to Windows or Mac OS X which should use their own native configuration
locations.  (On Windows, we currently do this by working under %APPDATA%.  The
Mac OS X equivalent would be ~/Library/Application Support/Bazaar but there is
also cultural support for ~/.bazaar on that platform.)

* If $XDG_CONFIG_HOME/bazaar exists, use the files there for configuration,
  noting in the log that we are doing so.  This allows individuals who would
  like to use the XDG specification to do so.
* Due to a lack of consensus on where plugins should live under the XDG Base
  Directory spec, continue to look for plugins in ~/.bazaar/plugins.  To
  change this directory to something not under ~/.bazaar, use the environment
  variable $BZR_PLUGIN_PATH.