resolved issue 252 - allow admin to adjust bcrypt effort
updated upgrade script
added open_registration parameter during install or upgrade
issue 255 - refactored some preference setting code to remove code duplication.  Should split up prefs.php into the view and controller (separate files)
separated the markup from the logic in prefs.php.  Broke into two files, set-prefs.php and prefs.php.  set-prefs.php can be used for XHR
allowed admin to enable/disable registrations, display registration link on login page if allowed
completed registration page (more or less) including email confirmation.  Need to clean up the code in register.php
fixed issue 258, persistent login fixed
resolved issue 257 - cleaned up use of FOF_BASE_URL
resolved issue 17 - new users can now register