rubymotion/BubbleWrap — pull request #100 by compressed (2012-07-15 15:19:16+00:00)
Title: Support Content-Type when headers are provided

Hi,
I was running into trouble reading a payload from a rack server when specifying custom headers. I tracked it down to the fact that when I specified headers, I effectively blew away the Content-Type header, which made rack unable to understand the payload properly.

For example.. I wound up with something nasty like this:
```ruby
{"\r\n--BCB484F7-1678-4B68-8708-692617B21B93\r\nContent-Disposition: form-data"=>nil, "name"=>"\"provider\"\r\n\r\nfacebook\r\n--BCB484F7-1678-4B68-8708-692617B21B93--\r\n", :format=>"json"}
```
Instead of:
```ruby
{"provider"=>"facebook", :format=>"json"}
```
This change should hopefully do the trick. Added tests too!

Thanks,
Chris