Nothing new to show 
I tried to use libraries with parity and stop bit options (no changes from original libraries), only thing I have changed is Serial.xxx to Serial1.xxx, so I can work with Leonardo (Leonardo for master and another Leonardo for slave).
Again same problem. Master can control slave, but cannot process answer from slave. Here is picture of communication from oscilloscope:
Oscilloscope settings:
Time - 5ms/div
RX channel - 2V/div
TX channel - 2V/div
From picture above we can see that answer from slave is a bit shorter than master request. I think this is all right, or maybe not? But anyway, this is what master gets as an answer from slave, but still does not react on this answer.
JuanB: on what hardware were you testing this library? I realy don't think that hardware can cause this problem, since master can control slave, but who knows.
And many thanks for all help!