Add isPossibleNumber and isPossibleNumberWithReason
Merge branch 'PrefixMapper' of https://github.com/giggsey/libphonenumber-for-php into PrefixMapper

* 'PrefixMapper' of https://github.com/giggsey/libphonenumber-for-php:
  Incorrect JSON from previous commit
  We now replace giggsey/libphonenumber-geocoder