Added <email_idsname> option to the ossec.conf

This feature adds an addational option to the ossec_config/global config
block in ossec.conf called <email_idsname>. the value of this field gets
added o the email headers as "X-IDS-OSSEC: $value" to make sorting of
emails from different masters easier.

Example:

<ossec_config>
  <global>
    <email_idsname>ossec.dev</email_idsname>
  </global>
</ossec_config>
Fixed some stntax errors that made it through.

Still WIP, need to finish up the tests and see if I got everything
relevant from our larger patch.