Release of 0.4.0

* Sun Jan 20 2019 Trevor Vaughan <tvaughan@onyxpoint.com> - 0.4.0-0
  - Add the ability to set the 'max_open_files' ulimit
  - Add Incron::Mask Data Type denoting valid incron masks
  - Add `incron::purge` parameter to optionally delete all unmanaged files in
    `/etc/incron.d`. This may be enabled by default in the future but is
    currently disabled to preserve the existing functionality.
  - Added support for the new options starting with 0.5.12
    - Automatically strip out options that are not supported by earlier versions
      for seamless backward compatibility