Add alternative email addresses to the model

A new struct is created named EmailAddress that contains alternative
email addresses for users. Also the email related methods; IsEmailUsed
and GetUserByEmail are updated.

DeleteUser deletes the extra email addresses and DeleteInactivateUsers
also deletes inactive accounts. This could be factored out, but should
do it for now.
Add function to the model for email address management (add/delete/activate)
Method for activating email addresses through verification email
Template for email activation email
Finish method for having multiple emails/user.

All basics are implemented. Missing are the right (localized) strings
and the page markup could have a look at by a frontend guy.
Rewrite of SendMail function

The SendMail function is rewritten and has the following new functionality:
 - It is optional to skip verification of keys. The config option SKIP_VERIFY is added
 - If the port is 465, or ending on 465, the TLS(/SSL) connection is started first.
Add option to use CRAM-MD5 as authentication method in the mailer
Prefer CRAM-MD5 over PLAIN authentication
Merge pull request #761 from phsmit/mailer_rewritten

Rewrite of SendMail function
Merge pull request #762 from phsmit/crammd5

Crammd5
update locale and mirror code format
Remove standard mailer port lines

This lines got committed by accident. They do actually nothing, as SplitHostPort will give an error if port is not given.
Change from header in email, fixes #765
Remove unused "User" member of Message Struct and fix bounce address

The User member of a message is not needed anymore.

The from that is send to the server, should always be the "system" from. This is also called the Bounce address http://en.wikipedia.org/wiki/Bounce_address
Parse the from string to extract the email address
Merge pull request #764 from phsmit/fix_mailer

Remove standard mailer port lines
Small fixes to multiple_emails feature
Merge pull request #755 from phsmit/multiple_emails

Multiple emails
mirror fix and update
Merge pull request #766 from phsmit/correct_from

Correct usage of FROM in email creation