Properly shutdown debugger threads on exit

Summary: When the server quit we were leaving the proxies
running. This led to an assertion in dbg builds when the
proxy was destroyed, and random crashes in release builds.

Reviewed By: @jdelong

Differential Revision: D1596601
Fix more hhbbc issues with enums

Summary: Name-only resolutions weren't handled in the last diff.

Reviewed By: @markw65

Differential Revision: D1596483