Added top-level exception catcher in main().
Added top-level exception catcher in main().

nanocad-lab/X-Mem,mgottscho/X-Mem,nanocad-lab/X-Mem,Microsoft/X-Mem,mgottscho/X-Mem,mgottscho/X-Mem,Microsoft/X-Mem,nanocad-lab/X-Mem,Microsoft/X-Mem,nanocad-lab/X-Mem,mgottscho/X-Mem,Microsoft/X-Mem