Add package for Timer.  Use SpinWait struct to simulate the Thread.Yield.  According to MSDN it will always yield after the initial several spins.  Simple test shows it yields after 11 spins.

Replace StringComparer.InvariantCultrueIgnoreCase with STringComparer.OrdinalIgnoreCase as the former is almost always incorrect for string equality.

Disable logging of ThreadPool stats for netcore since Get{Max,Min,Available}Threads() are not supported.

Replace unsupported Environment.MachineName with Environment.GetEnvironmentVariable("ComputerName") call.

Remove usage of ThreadPriority for netcore.

#248 Exchanging operands in the ternary operators of server selection in TryResend in ServerSelectionStrategy

Exchanging operands in the ternary operators of server selection in TryResend in ServerSelectionStrategy

Add ClientName to output for timeout messages

Conflicts:
	StackExchange.Redis/StackExchange/Redis/PhysicalConnection.cs

Added `defaultDatabase`

Default SslHost in clustering mode

added IConnectionMultiplexer interface to facilitate better unit testing

fixed ClientName summary doc typo

Update Configuration.md

In clustering mode currently, ClusterConfiguration for every server endpoint is built using the output of "CLUSTER NODES" command which consists of IP addresses of the nodes inside the cluster (SetClusterConfiguration and UpdateClusterRange methods)
However, when we try to authenticate the client to the ssl endpoint, inside SocketMode ISocketCallback.Connected, using the ssl.AuthenticateAsClient method it throws an exception
"The remote certificate is invalid according to the validation procedure” since we are trying to authenticate using the IP address as opposed to the Dns Host name.
An existing workaround this problem is to configure "SslHost" explictly inside the connection string or specify it inside ConfigurationOptions.
However if the users of the client do not configure this explicitly, it is a reasonable fallback behavior to infer this information from the specified server endpoints. The fallback behavior will be as follows:
If all the endpoints inside the configuration are dns endpoints and have identical hostnames, the SslHost is the dns host name for one for one of these endpoints.

Update documentation for Scripting and Profiling