[PD] [pii2c] keeps and resends previous messages when addresses change

[Alexandros]

When trying to send messages to two I2C slaves from the Pi with [pii2c]
the following happens:

If I send this message to [pii2c 0x0A]:
"write 3 127 7"

it arrives properly at the slave address 0x0A.

If I change the address to 0x09 with the message "addr 0x09" and then
send this message:
"write 97"

then both messages will be sent to the respective slaves, meaning that
"3 127 7" will be sent to slave 0x0A and "97" to slave 0x09. If I then
change the message sent to 0x09 to "98", this will be sent to 0x09, but
again "3 127 7" will be sent to 0x0A. If I resend "3 127 7" to 0x0A,
"98" (the last message set to 0x09) will be sent to 0x09 as well.

The same behavior occurs when I send the message "write 0x09 98". The
same behavior also occurs if I use two different [pii2c] objects, like this:

[write 3 127 7(
|
[pii2c 0x0A]

[write 97(
|
[pii2c 0x09]