text: // JSON <template>
  // Mail / A template object
  // 
  // Describes how an e-mail subject, text body or HTML 
  // body should be build based on information about the
  // sender, the recipient and the mail draft's own properties.
  //
  // A type of [template](/docs/#/types/template.js): refer to
  // that document for general information about templates and template syntax,
  // and to this document about specific variables available to e-mail templates.
  //
  // All e-mail templates (subject, text body and HTML body) support the same
  // set of variables.
  // 
  // # Sender information
  //
  // The sender is specified as the `from` field during [draft 
  // creation](/docs/#/mail/create.js). It is available from the template
  // as variable `from` with the following properties: 
  //
  // - `from.email`: the e-mail address of the sender. This also appears
  //   in the e-mail's `From:` header.
  // - `from.givenName`: _optional_, the sender's given name, if any. 
  // - `from.familyName`: _optional_, the sender's family name, if any.
  // - `from.name`: _optional_, the sender's full name, if any.
  // - `from.label`: a string describing the sender. This is usually 
  //   either `email` or `name`, but may take other more relevant values.
  //
  // All these variables match their corresponding definition in the
  // [person object](/docs/#/person/import.js).
  //
  // # Recipient information
  //
  // The available information is the same as for the _sender_ (above), 
  // and can be accessed through variable `to`.
  //
  // ### Example use of 'to'
  // 
  //     { "script": "$0;to.label;$1",
  //       "inline": [ "Dear ", ", ..." ] }
  //
  // # Custom e-mail data
  // 
  // This is a custom JSON object provided as the `custom` field during [draft 
  // creation](/docs/#/mail/create.js). It is available from the template
  // as variable `custom`.
  //
  // # Tracking links
  //
  // Variable `self` redirects to the URL provided as the `self` field 
  // during [draft creation](/docs/#/mail/create.js). If that field was not
  // provided, the variable is not available to the template. This redirection
  // includes [authentication](/docs/#/mail/auth.md).
  //
  // This is known as the **self link**.
  //
  // ### Example use of 'self'
  //
  //     { "script": "$0;self",
  //       "inline": [ "If you cannot view this e-mail, click here:" ] }
  //
  // Variable `track` is always available to the template, and contains a 
  // tracking URL for that specific e-mail. Visiting the URL returns an empty
  // one-pixel GIF image, and will count the e-mail as _opened_ but not
  // _clicked_ (all other tracking links count as _clicked_). 
  // 
  // This is known as the **track link**.
  //
  // ### Example use of 'track'
  //
  //     { "script": "$0;track;$1",
  //       "inline": [ "<img src='", "'/>" ] }
  //
  // Variables `urls` and `auth` are two arrays that both correspond to the
  // `urls` field provided during [draft creation](/docs/#/mail/create.js).
  // The difference is that `auth` includes [authentication](/docs/#/mail/auth.md)
  // while `urls` does not.
  //
  // These are known as the **body links** and **authenticated body links**.
  //
  // ### Example use of 'url'
  //     { "script": "$0;urls[0];$1",
  //       "inline": [ "<h1><a href='", "'>Adorable kittens available</a></h1>" ] }
  