Bug 988079 - [Calendar] day view sometimes adds duplicated days to the DOM r=gaye

not exactly the most "correct" solution (ideally we would avoid adding multiple unnecessary views to the DOM) but this fixes the problem and doesn't seem to introduce new bugs...

I tried to remove the other "frames" but I always ended up introducing more bugs.. (it also requires multiple changes to the unit tests). maybe it's better to merge this as is and create a follow up bug, since it would be just an optimization (not a real bug).

I think the multiple "frames" is a leftover from before Bug 791395 (when interaction changed from *panning* to swipe)..

PS: the multiple frames would be useful if we decide to add transitions during day changes.