As it turns out there are only two or three functions where we can do
this. It also breaks logging, and this function will probably only be
called once anyways. More consistency is always better.
This is quite a huge refactor, but note everything is consistent (and
we're going to need one or two more of these `Vst3*Proxy` objects).
Right now nothing extends `IHostApplication`, but this way it will be
trivial to add support for more host context interfaces.
Robbert van der Helm