Add test that exceptions can cross DLL boundary

[bmerry]

This will require a separate test binary, since the current one is statically linked to get at the internals.

Reported by: bmerry

Original Ticket: clogs/tickets/10

[bmerry]

• milestone changed from 1.0 to 1.1

It's a little tricky since it requires test-only code inside the library to deliberately throw clogs::InternalError, which I'd prefer not to add to the dynamic symbol table. Deferring until I can think of a nice way to do this.

Original comment by: bmerry