* Add possibility to configure GitHubClient timeout (#963)
A first attempt to fix the problem describe in #963 by adding a possibility
to extend the default timeout value (100s)
that is too short to be able to post assets in github release.
* Rename to SetRequestTimeout
Make comments consistent
This keeps the IHttpClient interface simpler and ensures the
deserialization responsibility lies outside of that class. It only
needed the Type parameter for a special case that could be handled in a
better way.
