Email class: Sent text or HTML e-mail messages using templates

This is a simple class that can be used to send text or HTML formatted e-mail messages using templates.

The class can configured to defined the sender address, recipient addresses, the subject text, the body text either in plain text or HTML formats.

Optionally the class can replace template marks in the message body by corresponding template variables.

If more than one recipient address is specified, the class sends separate messages to each recipient.