Import failed if there are rcs revisions with author is empty

How to reproduce:

• export without save author&versions
• import
• make many versions of some document (for create >1 full rcs revisions)
• full export
• import
  (not tested)

There is a bug in identifying of old format of archive. (= if author contains ".")

How to solve:

• Check what archive has old format by state(full/diff) for example, but not by author
• override patch() for full-state nodes for resolve future inconsistencies.