[nem-en] Debug support

[vc]

> I'm not willing to do this change at the moment, maybe in future if
> find some time.

It's very sad. :(

> Let me know if the overall debugging experience is now better.

It is a little. But debugging of match expression is still ugly.

And I can't set breakpoint on begin match (on match keyword).
The C# compiler add 'not' in begin and end all blacks (and some statements)
which allow set breakpoint.

>  If you
> give me some more examples, which work extremely ugly in debugger I
> will look at them too.

Another example is expression:
def x = SomeMethod();
If try set breakpoint on this line the debugger stop on assignment
expression. It prevent step into method. I am compelled add fake expression
(like assert(true);) to stop before expressions (of this kind).

One more example is a local method.
If exist code like this:
def f()
{
  ...
}

f();

I can't set breakpoint on 'f();'.

And it is necessary add 'nop' with debug information to begin and end of
each block. It will allow check return value and set breakpoint before some
code fragment.