ENH: Enable ACF and PACF plots to accept array inputs
ENH: Enable ACF and PACF plots to accept array inputs

Enable array input to show only specific lags
Change CI behavior to not include 0
Refactor both plots to exploit common structure
Add new kwarg, zero, to include/remove lag 0 from plot

closes #2430
closes #1658

josef-pkt/statsmodels,phobson/statsmodels,yl565/statsmodels,josef-pkt/statsmodels,phobson/statsmodels,jseabold/statsmodels,josef-pkt/statsmodels,jseabold/statsmodels,jseabold/statsmodels,bashtage/statsmodels,statsmodels/statsmodels,statsmodels/statsmodels,ChadFulton/statsmodels,statsmodels/statsmodels,jseabold/statsmodels,bert9bert/statsmodels,yl565/statsmodels,statsmodels/statsmodels,bert9bert/statsmodels,phobson/statsmodels,ChadFulton/statsmodels,bashtage/statsmodels,josef-pkt/statsmodels,bert9bert/statsmodels,jseabold/statsmodels,phobson/statsmodels,phobson/statsmodels,bashtage/statsmodels,yl565/statsmodels,josef-pkt/statsmodels,ChadFulton/statsmodels,statsmodels/statsmodels,ChadFulton/statsmodels,bashtage/statsmodels,statsmodels/statsmodels,ChadFulton/statsmodels,josef-pkt/statsmodels,bashtage/statsmodels,bashtage/statsmodels,yl565/statsmodels,ChadFulton/statsmodels,bert9bert/statsmodels,bert9bert/statsmodels,yl565/statsmodels