css format changes

It happened again: New crm114 version doesn't read css files from
previous crm114 versions correctly and causes trouble up to mail loss to
Debian users.

The problem is that one usually upgrades whole system from a
distribution, without paying special attention to particular packages.
After upgrading crm114 from 20080330 to 20090423, the newer crm114 reads
the input (e.g. incoming mail) and the old css files, produces an *empty
output* and exits with the *exit code 0* (at least on my computer and
computers of some other Debian users).  So a typical user upgrades his
computer and sooner or later he finds out crm114 is working erroneously
and *all the incoming mail got silently lost in the meantime*.

Would it be possible to fix this behavior?  Of course, the best solution
from the user's point of view would be to make the css format stable.
If this is not possible, crm114 should at least detect the
incompatibility and exit with a non-zero code to prevent "successful"
e-mail delivery.

What do you think?



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