Squashed commit of the following:

commit 8ab8f77557a98adad56006e6d372d8f348191742
Author: daniel oeh <daniel.oeh@gmail.com>
Date:   Wed Nov 12 16:05:32 2014 +0100

    Use OkHttp instead of HttpClient in HttpDownloader

    - Adds support for SNI -> fixes #354
    - fixes #548

commit 38278bc72abcdc190d44f26593f6efdd2b390877
Author: daniel oeh <daniel.oeh@gmail.com>
Date:   Wed Nov 12 15:04:32 2014 +0100

    Use OkHttp instead of HttpClient in GpodnetService