* Rework WiFiClient
Rework WiFiClient to correct error where making a copy of a WiFiClient object resulted in the socket being closed prematurely.
Added loop and select to write to handle/prevent EAGAIN errors.
* Rework WiFiClient to use shared_ptr
Rework changes to utilize shared_ptr rather than manually maintaining reference count.
Revert changes to write
* Incorporate comments from review
Move WiFiClientSocketHandle and fd() into WiFiClient.cpp
