Interpreter for circuits

[mariari]

It would be nice to have an interpeter for circuits, so we can submit code run the interpeter and give back data.

This way we can write tests over our custom gates and other such niceities.

Automatic behavior

If the current gate is invoked on a top level setting, we should run the interpreter and give back a result.

However if the current gate is being executed in a defcircuit or a defgate then we should not execute it, rather having the normal behavior of emitting a call.

I think this can be easy to do with a dynamic variable that marks that we are compiling within a circuit, so have normal calling behavior