Option to clear/ignore EEPROM

[jgfoster]

Kirt reports that Lloyd Trueblood has a device that reboots constantly and appears to have bad data in EEPROM. We should have an option to reset/ignore EEPROM on boot, probably with a keypress. We have the option to not connect to Ethernet on boot (Ethernet_TC.cpp:18-19) if any key is pressed. We should refine this so that one key deals with EEPROM and another deals with Ethernet.