making import procs report errors encountered. Making message::register proc throw error if en_US message doesn't already exist. Adding message::revert proc.
leaving sync_time null and not assuming we were ever in sync. This has the downside that we have no base when bootstrapping the new upgrade feature causing a lot of update conflicts. However, it avoids delete conflicts.
Adding optional cascade parameter to bcms::folder::delete_folder todelete all children. Default is false. Addbcms::folder::content_types_select to generate a list of lists ofoptions for valid content types for a folder.
