Support for internationalized .IT domain names

The IT tld has recently added support for internationalized domain names.
The validation failed to pass for domains such as città.it which are now perfectly valid.
Reverted GR validation rule
Fixed eszet character validation in .it idn domains
Add .it idn domains unit tests
Merge branch 'hotfix/3081'

Close #3081
Fix #2574
Merge branch 'patch-2' of git://github.com/mtorromeo/zf2 into hotfix/3272
Merge branch 'hotfix/3272' into develop

Forward port #3272