Bump spatial-events req

Recent changes fix a fairly gnarly bug in the octree generation.

Went with >= 0.0.1 because:

1. I want to add a method to limit the maximum number of octree nodes
2. I want octree nodes to garbage collect themselves once they're empty (with an optional "ee.gc()" to detach all references to orphaned nodes
3. I want to make it simple to "move" listeners over time.