[nem-en] Typing a expression in context of method

[vc]

> > Add will be very nice if Typer will get reference to Messenger parameter
> > instead of get it from solver (in Integration we type methods in lazy
> manner
> > and we need intercept messages from typer).
> >
> 
> AFAIK Messenger is used for "potential errors", so there might appear
> some error messages for correct code, because Typer uses
> "backtracking" to resolve for example choosing overloaded functions.

OK, but we need intercept real error messages which give out Typer.
Now we catch error messages in Message *module*.
The Message shold be class. Reference to it shold be put to Typer.

Theoretically Typer can run in parallel. 
It would accelerate compilation on multiprocessor systems.