Description of problem:
Some plugins are working, some are not. Specifically, I need vCalendar plugin to
work, but others (I've tried Notification and AttRemover) don't work either.
They seem to be rebuilt (with a "bump" change log) when 2.10 came out, but
that's not enough, as it seems.

How reproducible:
Always.

Steps to Reproduce:
1. install claws-mail-plugins,
2. in claws-mail, enter the plugins manager,
3. tell it to load plugins, use ^A to load them all at once,
4. see for yourself, which ones don't work (they're italic and their description
contains additional information).