KAKU TX: Fix command parsing

[lennart-k]

Hey, first thanks a lot for maintaining this awesome project. :) When trying to send commands like

10;Kaku;00004c;0d;OFF;

I would get wrong house and address. Also str2cmd couldn't deal with trailing ; for ON|OFF. As a fix I've replaced ; with the end-of-string character and tried to tidy up a few lines. It now works perfectly fine for me :)