Ignore a given value at "unique" validator rule

This is usefull if we have a profile area that allows the users to update their own email or login.

So is possible to check if input email/login already exists without conflict with it self.

Eg 1: ['email' => "unique:table,email,ignoreme@domain.tld"]
Eg 2: ['nick' => "unique:table,nick,ignoremylogin"]
Merge pull request #81 from aldoanizio/patch-1

Ignore a given value at "unique" validator rule