Announce. script to get the sysfs gpio file associated to a pin name

General Discussion
1

I found several time the little problem of getting the GPIO file in sysfs associated to a pin name.
I developed a little script to solve the problem once and for all. I tested it a little in BB-Black and BB-AI and it seems working fine. It may be useful to other users so I post it here.

Bye
Nicola