pointer to invalid LuaState in LuaObject

[IntendedConsequence]

In LuaObject's contructors and assignment operators, if src LuaObject happens to come from a coroutine then this LuaObject LuaState L will point to freed memory once the coroutine is garbage collected. Which results in all kinds of nasty business, especially in production code :(
From reading the reference, it appears that using lua_pushthread's return value of 1 for a non-coroutine lua_State should help identify that case and lua_xmove should transfer the object for a proper fastref in this's LuaObject's LuaState.

luaplus51-all/Src/LuaPlus/LuaObject.inl

Lines 76 to 89 in 7eb904c

	inline LuaObject::LuaObject(const LuaObject& src) throw() {
	if (src.L) {
	L = src.L;
	#if LUA_FASTREF_SUPPORT
	ref = lua_fastrefindex(L, src.ref);
	#else
	lua_getfastref(L, src.ref);
	ref = lua_fastref(L);
	#endif // LUA_FASTREF_SUPPORT
	} else {
	L = NULL;
	ref = LUA_FASTREFNIL;
	}
	}