message: Add formatters for c strings
  This stops it from crashing when a nullptr is passed as a char*.
diff: @@ -37,6 +37,35 @@ namespace fakeit {
  }
  };
  + template <>
  + struct Formatter<char const*>
  + {
  + static std::string format(char const* const &val)
  + {
  + std::string s;
  + if(val != nullptr)
  + {
  + s += '"';
  + s += val;
  + s += '"';
  + }
  + else
  + {
  + s = "[nullptr]";
  + }
  + return s;
  + }
  + };
  +
  + template <>
  + struct Formatter<char*>
  + {
  + static std::string format(char* const &val)
  + {
  + return Formatter<char const*>::format( val );
  + }
  + };
  +
  template<class C>
  struct Formatter<C, typename std::enable_if<!is_ostreamable<C>::value>::type> {
  static std::string format(C const &)
  