MailGW.handle_message(): as config is used many times in this method, have a local variable instead of going through self.instance.config each time; change config attribute access to container (item) access; where possible, avoid duplicate computing of config settings; fix MAILGW_KEEP_QUOTED_TEXT and MAILGW_LEAVE_BODY_UNCHANGED - config values are boolean now; trim trailing spaces, fix vim modeline

This file contains items that need doing before the next release:

Required:
- documentation of i18n: TAL tags for translation
- translation databases in trackers
- implementing logging for roundup-server, including command-line switches
- per-property permission spec


Optionally:
- have rdbms backends look up the journal for actor if it's not set
- migrate to numeric ID values (fixes bug 817217)