Fixed issue with duplicated Http Headers

[rickykaare]

When a header was having multiple values, the iOS solution was to pick the last, and the Android solution was to create multiple headers.

I believe the correct behavior is to separate each value with a comma.

Example:

In the current implementation I was getting 400 - Bad Request responses because of the headers being sent from my Android device looked like this:

User-Agent: Android/4.1.1
User-Agent: Music.Droid.Msh/1.0.0.0
User-Agent: Rev/local
User-Agent: E247.Api.Client/0.1.0.157
User-Agent: (Google Nexus 4 - 4.1.1 - API 16 - 768x1280 vbox86p)
Accept-Language: en-US
Accept-Encoding: gzip
Accept-Encoding: deflate

With the suggested changes the headers would render like this:

User-Agent: Android/4.1.1,Music.Droid.Msh/1.0.0.0,Rev/local,E247.Api.Client/0.1.0.157,(Google Nexus 4 - 4.1.1 - API 16 - 768x1280 vbox86p)
Accept-Language: en-US
Accept-Encoding: gzip,deflate

[anaisbetts]

Thanks!