Make AddressChanger interactive

[Xayton]

The address change is now interactive: you can scan the I2C bus and change the address of each modifiable modulino.
All of this can be repeated without having to recompile the sketch and upload it to the board.

This is an example of output provided by the sketch on the serial:

ADDR	MODULINO	PINSTRAP	DEFAULT ADDR
0x1E    Buzzer          0x3C            0x1E        
0x36    Smartleds       0x6C            0x36        
0x37    Smartleds       0x6C            0x36 *      
0x38    Smartleds       0x6C            0x36 *      
0x3C    Encoder         0x74            0x3A *      
0x3E    Buttons         0x7C            0x3E        
0x50    Smartleds       0x6C            0x36 *      
0x66    Buttons         0x7C            0x3E *      
0x77    Smartleds       0x6C            0x36 *      
Enter the current address, space, and new address (ex. "0x20 0x30" or "20 2A"):
  - Enter "<addr> 0" to reset the device at <addr> to its default address.
  - Enter "0 0" to reset all devices to the default address.

• devices are recognized either by their (fixed) address or by sending a message and reading the pinstrap result
• for each device it will also show if the current address has been changed from the default
• allows to reset the address of a device (or all of them) to the default, by setting the requested address to zero