Connect options

[jadamcrain]

Adds overloaded constructors for creating a TCP/TLS master channel that takes an opaque ConnectOptions. The new parameter provides a way to set:

• An optional timeout that may be less than the OS default connect timeout. If not set, the behavior just reverts to the OS default timeout.
• An optional local endpoint to bind the socket prior to connecting. This is useful in dual-homed systems with multiple NICs. If not provided, then the behavior reverts to all adapters and an OS specified port (0.0.0.0:0). Most users wishing to specify the IP of the adapter will chose to use 0 for a random available port from the OS, but manual port selection is possible as well.

This is a proposed way of addressing #245 and #244 without breaking backward compatibility. Some of the various options, like the retry paramters, could be merged in a future 2.0.