Fix flickering labels and disappearing quest pins

[Helium314]

This is the PR for #136.
I honestly have no clue why it helps, especially because setting priority without toString works as expected in place-labels

[westnordost]

Shouldn't the same fix be made for every other place where a javascript function returns the priority?

[Helium314]

I tested for place-labels, and there priority works with and without toString, and I haven't seen any disappearing quest pin or flickering label in the tests I did with the current PR state.

So I would say it's not necessary to apply the fix in other places, as there is nothing else to fix... which is why I mentioned above that I have no clue why the change actually helps.
I think it shouldn't help, but it for some reason it does. I can only encourange you to go to the house in streetcomplete/StreetComplete#4522 (comment) and try for yourself...

[westnordost]

I can only encourange you to go to the house in streetcomplete/StreetComplete#4522 (comment) and try for yourself...

Actually, I can't reproduce the issue at that house already now. Do you know another location where the current issue is reliably reproducible?

[Helium314]

Still works for me: go to max. zoom, zoom out two steps (or one and rotate) and the pin is gone.

[westnordost]

Which pin for example?

[Helium314]

The pin for the building type quest. Looks like this (49.2 from F-Droid):

[westnordost]

Right. I can reproduce it there. And I fiddled around some more, adding semicolons, wrapping the other functions in toString etc. and it looks like this is the only and the minimal fix to workaround this odd bug in tangram. Thank you!