ReflectionProperty::has/getDefaultValue

Hi everyone, until now there was no way on ReflectionProperty to easily find out if a value has a default value and what that default value is. Essentially the way was indirectly through ReflectionClass::getDefaultProperties(). In combination with typed properties and Reflection use cases (for code generation for example) it is interesting to know when a property has no default value, because accessing it through ReflectionProperty::getValue($object) would otherwise throw a "property unitialized" error. I have added a PR adding these two functions and looking for more feedback from interested parties: https://github.com/php/php-src/pull/5071 This addition is small so that I believe an RFC is not necessary, given that it is more "missing functionality" that should have been there before greetings Benjamin