Added support for getting phoneNumber

The contact info response now has a new key "phoneNumber" which contains either an empty string or the contact phone number.

An empty string was choosen instead of null when the contact has no phone number for convenience since Objective-C doesn't suppor having nil values on its dictionaries.
Added missing import statement
Merge pull request #5 from albertein/add_phone_to_results

Added support for getting phoneNumber