Add simple EEPROM implementation for RPi

This implementation provides EEPROM like
storage for information. Its size is 1KB.
It provides the same functions as on AVR
and as used by MySensors.

Signed-off-by: Tomas Hozza <thozza@gmail.com>
Use PiEEPROM for EEPROM operations

Signed-off-by: Tomas Hozza <thozza@gmail.com>
Add PiGatewaySerial draft

Signed-off-by: Tomas Hozza <thozza@gmail.com>
Add signal handler

Signed-off-by: Tomas Hozza <thozza@gmail.com>
Implement the serial interface for Gateway

Signed-off-by: Tomas Hozza <thozza@gmail.com>
Build the PiGatewaySerial

Signed-off-by: Tomas Hozza <thozza@gmail.com>
Fix the number of written bytes to the tty

Signed-off-by: Tomas Hozza <thozza@gmail.com>