Update zoom_merge with master updates (after wrangling immense conflicts)

Updating the zoom branch... after painfully going through a ton of conflicts!

@matthieu fixed up the test. At the size of the time values I see +1 shouldn't be representable, so to me the mystery is why it worked in the first place. Maybe the absolute size of time has increased!

Never had issues with any other compiler before. But the fix makes sense! No idea why it ever worked.

added zooms label

requested review from @matthieu

assigned to @matthieu

mentioned in commit 3f46844a

merged