[svn] * TODO,content.c,lock.c,server.c,server.h: Remove bug notice re: need to do a Cont_write on Lock_closeDatabases in case of unwritten content changes when releasing the lock. Update content to keep dirty flag and avoid unnecessary writes, and lock to signal server to re-read its group content info after the lock is released. Do NOT write content info on Lock_close if dirty, as the placeholder article in unsubscribed groups is currently done by adding it to the content when joining the group and deliberately not saving it unless another content modification takes place and thus causes the content to be saved.