saveSimList() documentation out-of-date

[achubaty]

• documentation says rds files can be used, but qs is forced (saveSimList() forces use of qs #259);
• fileBacked* args are deprecated and should be removed from the documentation;
• it's unclear in the documentation that both a qs file and an archive (.tar.gz or .zip) are being created;
• it's unclear that when specifying .zip archive that .tar.gz is used anyway on Linux