Add PropertyTranslation.php
Add PropertyTranslation.php

- Intelligently translates from JSON property names to function names.

- This is the exact complement to FunctionTranslation, but this goes in
  the reverse direction: Takes a property name and tells us what
  function we should call to retrieve it.

- Both classes 100% match each other bidirectionally.

SteveJobzniak/LazyJsonMapper,aitte2/LazyJsonMapper,SteveJobzniak/LazyJsonMapper,aitte2/LazyJsonMapper