BF: the last message of a room was not listed when paginating from the MXMemoryStore.
BF: If the initialSync returns less messages than requested, we got all the room history from the home server it is useless (and leads to a duplicate event) to make pagination request to the HS later.
testSeveralPaginateBacks: Added duplicated events check
MXStoreTests: Make sure no messages are preloaded for the tests
Add more test on MXRoom.canPaginate which now have an additional dependency: the state of the current pagination from the MXStore
Merge remote-tracking branch 'origin/develop'