Code review comment for lp:~raof/mir/the-least-dirty-thing

From the client perspective it *is* an extension; libmirclient-debug-extension.so exposes only the three symbols we currently support; it's not a debugging version of the client library.

I can, of course, fold those symbols back into libmirclient. I think it's useful to have the non-core things split out a bit, though.