Speed up node selection

[fedarko]

Currently, a problem when visualizing really big trees (~200k tips) is that there's a delay of a few seconds between clicking on a node and seeing the selection menu pop up. From talking with @ElDeveloper this morning, it would be nice to speed this up.

The current code for finding the closest node to a mouse click checks all the nodes in the tree, so if we could quickly rule out a bunch of these nodes then that'd be nice :)

[wasade]

What about computing quadtrees over the tip coordinate positions? It should then be possible to use the x/y position of the mouse to get the set of tips present in a small portion of the screen

[fedarko]

Would definitely be a cool idea! I think Yoshiki and Kalen were discussing binary searching as another possible method?

[wasade]

It's kinda like a 2D binary search :)

[wasade]

@zoechallacombe, this is the issue I mentioned on our call where quadtrees may be beneficial