Ray

address issues 139 and 141

1

This pull request resolves #139 (`setSS` on ESP8266) and resolves #141 (`EthernetClient::write`).

On ESP8266, this works for all other GPIO pins except when GPIO 16 is used as CS: https://github.com/arduino-libraries/Ethernet/blob/75a3c37b5e513305b82e926ca6a4f8190f536c9d/src/utility/w5100.h#L415 Reference ESP8266's digitalWrite function: https://github.com/esp8266/Arduino/blob/master/cores/esp8266/core_esp8266_wiring_digital.cpp#L84

The return value of EthernetClient::write should be the return value of Ethernet::socketSend: https://github.com/arduino-libraries/Ethernet/blob/75a3c37b5e513305b82e926ca6a4f8190f536c9d/src/EthernetClient.cpp#L86 Otherwise if the buffer to be sent is larger than W5100.SSIZE it will only send W5100.SSIZE number...