This is suppose to fix the bug where maildrop and maildirmake doesn't rebuild the /maildirsize file. 

- Fixed bug with maildir creation in mail plugin.

Updated the Debian installation instructions.

Updated ToDo item list.

Moved server modules and plugins to new directory and updated the installer to create the symlinks for the modules and plugins from *-available to *-enabled directory.
Fixed a typo in mailfilter template.

Added a server module for clients and a mail plugin.