Major overhaul to the ThumbnailDefinition - RenditionDefinition conversion code.
Removed the imported rendition definitions acp, replacing it with the original rendering_actions_space xml.
git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@19129 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261