tour: add Italian translation.
tour: add Italian translation.

Change-Id: I387f441ace958b770630da2ac81dbe17a91fe6fc
Reviewed-on: https://go-review.googlesource.com/7042
Reviewed-by: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

shuLhan/go-tour-id,raindev/tour,campoy/go-tour-ua,LaPingvino/go-tour-nl,golians/tour,golians/tour,golang/tour,bbandaru/tour,zorion/go-tour-ca,phoorichet/tour,tamnd/tour,campoy/go-tour-ua,shuLhan/tour,ybin/tour,Go-zh/tour,tamnd/tour,Go-zh/tour,ybin/tour,shuLhan/tour,bbandaru/tour,raindev/tour,shuLhan/tour,golians/tour,scryner/tour,phoorichet/tour,LaPingvino/go-tour-eo,LaPingvino/go-tour-eo,dupoxy/go-tour-fr,LaPingvino/go-tour-nl,rofrol/go-tour-pl,scryner/tour,Go-zh/tour,LaPingvino/go-tour-eo,Jasperste/tour,rofrol/go-tour-pl,Go-zh/tour,Jasperste/tour,campoy/go-tour-ua,bbandaru/tour,dupoxy/go-tour-fr,tamnd/tour,scryner/tour,shuLhan/go-tour-id,ybin/tour,phoorichet/tour,shuLhan/go-tour-id,raindev/tour,zorion/go-tour-ca,dupoxy/go-tour-fr,LaPingvino/go-tour-nl,Jasperste/tour,rofrol/go-tour-pl,scryner/tour