Debian packaging

Some notes:

* This depends on the cmake-patches branch being applied.  The first two commits are just replicated from the cmake-patches branch (maybe there's a better way to do this in github?  I'm somewhat new).

* This patch no longer converts to CDBS.  That was just the first thing I thought of when adding the CMake flags.  But you're right that it's easy to do with just debhelper.

* This patch adds support for -dbg packages.