[nem-en] Debug support

[vc]

The Nemerle compiler is successfully moving to the release. But there is one
important problem, not solved up to this moment. It is the support for
debugging.

.Net programmers do have a habit of using debugger.
But ncc generate very bad .pdb files.
We need to make efforts for elimination of this problem.

This is an intricate problem which can be solved only by the compiler team.

Kamil, Michał, please, find some time to solve this problem.