Fixed #3315 by disallowing duplicate ids in drilldown.
Fixes #3317, extra tick added when there are only two ticks (start and end)

Fix for a regression due to issue #3195, where all ticks were removed in
very short axes.
Solution is to add an extra tick if the number of ticks drops to 0
(practically the same as the previous bugfix)
Merge remote-tracking branch 'upstream/master'