ENH: moving average with exact terms in window

Refer EP#430

mentioned in commit 4648b8660db4c070040ad7be8ccb56f3ae66b0e5

mentioned in commit 692472b85e5095a608a4da0f56ffe64234ccb632

mentioned in commit 63e16f1fd4047cba8f726871d7ec27b51d6872b4

mentioned in commit 2e4e120030961d17f6a6905a63552db834bc3001

mentioned in commit 92dc2adecf6114270a67c06cb1bb298f689c8713

mentioned in commit 5c855131652b1ee24ca4bc86dc0394ea3abad159

mentioned in commit 4ba2a7afa187e14ddc13c328f805f7d76d3667bd

mentioned in commit 71cceab735bb42e919342882bf122f38f7122e1e

mentioned in commit 879ec4ee

closed