proxy functions should take C++ classes

[gdfast]

Currently, the implementations of the proxy() and proxy_steerable() functions take void * arguments just like the C ZMQ API instead of these cppzmq classes (like zmq::socket_t for sockets instead of void *).

cppzmq ought to do the appropriate accessing/casting work in the proxy functions instead of the caller.

[szmcdull]

In Visual C++, I don't need to cast. But in g++, I have to cast zmq::socket_t to void*. I suppose the c++ binding should avoid such casting?

[gdfast]

That's basically what I'm thinking. Especially because the point of zmq.hpp (in my mind) is to replace the ugly/unfortunate void* c structs with nice C++ objects. And if the user/developer has created two sockets that he/she wants to proxy, the call ought to be more along the lines of
zmq::proxy(socket1, socket2) and not zmq::proxy((void*) socket1, (void*) socket2)

(I'm using clang++ to compile for whatever that's worth)

[gummif]

Issue has been solved by #301