Plugin OpenDKIM: Update according plugin API 0.2.1, changed some functions, updated the README file and added a new config value.
Plugin ClamAV: Update according plugin API 0.2.1, changed some functions, updated the README file.
Plugin Postscreen: Update according plugin API 0.2.1, changed some functions and updated the README file.
Plugin Postscreen: Change SMTP port in Roundcube main.inc.php
Plugin RoundcubePlugins: Update according plugin API 0.2.1, changed some functions and updated the README file.
Plugin SpamAssassin: Update according plugin API 0.2.1, changed some functions, updated the README file and added a new config value.
Fixed small typo on plugins README.
Merge pull request #15 from reneschuster/master

Updated plugins ClamAV, OpenDKIM, Postscreen, RoundcubePlugins and SpamAssassin