Create C++ wrapper

[SasLuca]

It can be very useful to have a dedicated C++ wrapper that can also provide some utilities using C++ features like function overloading or default parameters (eg: allocator parameters can default to the heap allocator).

This wrapper can do the following:

• Use namespaces for all the names instead of rf_.
• Use constexpr for all the constants instead of macros.
• Make rf_context into a class with methods.

What to avoid:

• RAII (aka destructors)
• Exceptions
• RTII
• Virtual Dispatch

[SasLuca]

I started working on this.

[SasLuca]

Decided against this for the moment.