allow user to send content type as multipart header.

Hi Kevin!

I am working on an Android App which interact with rest-API server, and I find your HttpRequest very handy and well written. Thanks for your good work!

When uploading file to my server, it required me to send "content-type" as (multipart) part header, which seems cannot be done on original design (?). So I made a little change, allowing user to pass content type as argument to "part" call.

If it's ok, I would like to contribute it back to mainstream, so other users can have this feature.
Thanks for HttpRequest again!


Michael Wang