SendMail operation improvements

• A checkbox that says if it is a HTML or plain/text email
• Ability to add a link to the doc that is input, using the notification-contrib.xml file contirbution for the host. At least, it should be possible to add a link to the document view. A system to add a direct link to a blob property would be useful also, but not a priority
• Correctly manage encoding so that if I put some accents in the parameter "body", it is correctly manage until it goes to the smtp server.

In the ftl tempaltes, there is the function "htmlEscape", I don't know what it is for, but it must be useful : ? Also dates should be able to be formated, but I think that it is already possible with the script function.

• A checkbox that add the file(s) (we should give an xpath, or, even better, a list of xpath) to the email for real document sending.