New port: devel/rttr -- Run Time Type Reflection

RTTR stands for Run Time Type Reflection. It describes the ability of a
computer program to introspect and modify an object at runtime. It is also the
name of the library itself, which is written in C++ and released as open source
library.

The goal of this project is to provide an easy and intuitive way to use
reflection in C++.

This will be used by an upcoming multimedia/kdenlive release.