Closing matured positions changes APR #93
Description
Several of the addLiquidity and checkpoint tests written in #82 have uncovered that the pool's APR is effected by matured positions. This isn't a new concept (it's relatively clear that this will happen since the share reserves are always updated in the same way and the bond reserve updates decay). As bonds mature, the APR will become increasingly distorted by the absence of new bonds.
The model may be fine the way it is (it's certainly cheaper); however, it would be good to do a deeper investigation of this issue once we have sandwich tests in place.