Make all functions from std.typecons "Proxy" inout

[sclytrack]

> struct S
> {
> void f() {}
> void f() const{}
> void f() immutable {}
> void f() shared {}
> void f() shared const {}
> }
> struct Proxy(T)
> {
> T o;
>


I'm new to the concept of "shared const". What is the difference when 
comparing to "immutable"?