Rayo fax: specifying headers

[crienzo]

We need to be able to specify identity and header for transmitted faxes:

identity: telephone number (spaces, digits, +) header: header line at top of each page

[benlangfeld]

So this (along with #84) are difficult because the output component's <document/> element is not flexible enough. We can't add children to it because those would be considered to be the document as inline data.

Three possible solutions:

1. Use some funky URL format like: http://example.com/my_fax.tiff?pages=2..4&identity=+140455555555&header=This%20is%20some%20header

2. Allow something like

   <output>
    <fax url="http://example.com/my_fax.tiff" pages="2..4" identity..../>
   </output>

3. Specify some document format for fax like so:

   <output>
    <document content-type="something">
      <url>http://example.com/my_fax.tiff</url>
      <identity>BLAH</identity>
    </document>
   </output>

I think I prefer option 2. Thoughts?

[crienzo]

option 2 is fine with me.