print_P for ETHER_28J60.h to save memory

Hi folks, first post here ...

I do some changes on ETHER_28J60.h by Simon Monk to enable print_P (for use with the F() macro) and put strings into Flash Memory. Well, I dont know if people are stil using this module (generally as a breakout board), but maybe this can be usefull for someone.

It´s simple to use ... write your code using e.print_P(F("Foo")); instead of e.print("Foo"); and that´s it. You can find a full example in my readme page on GH

You can find in my github page GitHub - fg1998/Arduino_ETHER_28J60.h-with-print_P: Implements Print::print_P for use with the F() macro to avoid RAM arduino usage issues

Cheers
fg1998