Merge tag 'refs/tags/0.3.0'
Remove dev tag from master.
Fix writers: Don't issue commands when an exception happened.
Fix issue with inherited fields.
Merge branch 'develop' into release-0.4.0
Jump to 0.4.0.
Resurrect dev tag in development branch.
Invalidate logs in the xoeuf shell.
Minor changes in docs and spaces.
Add a FIXME about probable documentation error. [med]
Fix documentation of get_dangling_modules.
Avoid touching when there are no fields.
Truly invalidate logging so that errors are visible.
Limit the traceback to 5 entries, since postfix will chop long ones.
Refactor `invalidate_logging` for nicer use.

The `invalidate_logging` was conceived to reduce the amount of logging
in xoeuf commands and, by extension, this covers OpenERP commands as
well.  So it was becoming a pattern to have to call it twice.

This patch removes this burden from the caller.
Log to syslog.
Log the raw email message if provided.
Report errors via email.
Remove spurious prints.
Send more data from failing incoming emails.