SYDNEY, Dec 31 (Reuters) - Australian shares are poised for a cautious start in Thursday's abbreviated session, with a slide in oil prices likely to weigh on energy shares. Pointing to a negative opening, share price index futures fell 0.3 percent to 5,276.0, a 43.9-point discount to the underlying S&P/ASX 200 index. The benchmark is still nearly 3.0 percent higher this month, but is on track to end 2015 down more than 1.0 percent over the year as a whole. In contrast, New Zealand
