first cut at custom commands

this basically works, functionality-wise
there are two issues, though:
-	the help doesn't work
-	the implementation is a bit wonky in several ways
-		the custom command !isa regular command, but rather contains it
-		this forces me to add attributes on-the-fly to the base App::VC::Command class (ick)
-		this is also what causes the help not to work
overall, this needs a better approach
but I need to commit what I have in case I need to fall back to it