Support Microsoft.Extension.DependencyInjection for .NET Standard 2.0

[pardahlman]

This fix should be similar to what was done in #257

[DotPete]

Hi @pardahlman, Any progress with this issue? We need your lib in our brand shiny new .Net Core 2.0 solution ;-)

[pardahlman]

Hello @DotPete - thanks for reaching out. #257 is resolved for 1.x of the client with this PR. This issue is for 2.x (now in RC1). You are more than welcome to submit a PR for this issue, or do something like this as a work-around

services
    .AddSingleton<IInstanceFactory>(c => RawRabbitFactory.CreateInstanceFactory(new RawRabbitOptions()))
    .AddTransient<IBusClient>(c => c.GetService<IInstanceFactory>().Create());