OpenWebMail 升级（2.10-2.30）

基本参照1.70到2.10的升级, 改动比较大的配置选项是以下几个方面的：

• The option has_savedsuid_support has been moved from etc/openwebmail.conf.default to etc/suid.conf
• dbm options are moved from etc/openwebmail.conf to etc/dbm.conf and etc/dbm.conf.default
• filelock option is moved from etc/openwebmail.conf to etc/filelock.conf and
  etc/filelock.conf.default
• remove: enable_setfrom, enable_setfromemail
• add: enable_loadfrombook, enable_editfrombook, frombook_for_realname_only
• add options webdisk_allow_untar, webdisk_allow_unzip, webdisk_allow_unrar,
  webdisk_allow_unarj, webdisk_allow_unlzh to openwebmail.conf.default
• move global setting in auth_xxx.pl into auth_xxx.conf so no more change to script
  itself is required for different cases.