RCMCardDAV v4.4.2

• Revert to a single release tarball. The new approach (compared to 4.4.1) to avoid the issue with conflicting
  dependencies between those coming with roundcube and those coming with the RCMCardDAV release tarball is to append the
  RCMCardDAV to the end of the autoloader list, so the roundcube dependencies are always tried first. This means if a
  library used by RCMCardDAV already comes with roundcube, RCMCardDAV will also use that version of the library. There
  is still possible problems left (i.e. package that only comes with roundcube might have a dependency for that an
  incompatible version is already included with roundcube). In the end, I don't think there is a clean solution to this
  issue. If you want to avoid this mess, don't use the release tarball but install using composer.
• No changes to RCMCardDAV itself