Handling SIGINT (Ctrl+c) and converting from python2 to python3

Hi,

I updated your code from python2 to python3 (using 2to3 and the pyxhook.py that I use in my own projects).

I also created a simple signalhandler for SIGINT to permit pyty.py to be quitted by Ctrl+c.

Finally, I made pyty.py executable (for my convenience).

Cheers,
Denis
This function does not follow the naming conventions of the other functions in this library. I suggest `sigint_handler` instead.