Cleanup ITransport for better extensibility

[icanhasjonas]

The current ITransport implementation handles connection pooling etc.. but unnecessarily exposes some specialized methods in the interface;

I propose you remove the following methods from the interface, making custom Transport implementation cleaner..

IList<Uri> Sniff();
void SniffClusterState();
bool Ping(Uri baseUri);
Task<bool> PingAsync(Uri baseUri);

(I personally like properties like the Settings and Serializer to be gone too... they shouldn't be part of the contract)

[icanhasjonas]

(That is, remove them from the interface, but keep them in the current implementation.. should be fairly easy and straight forward.. )

[icanhasjonas]

Would be nice to have an ElasticClient constructor that takes settings and an ITransport too..

[Mpdreamz]

@icanhasjonas this has now been implemented, the methods are also gone from the ITransport interface.

[Mpdreamz]

I would be interested hearing back about your custom ITransport implementation as well @icanhasjonas !