Don't explode when trying to free a NULL tree
Don't free polygons during the vertex tree free
Free the edge tree when we free the index
WIP: The new vertex_tree, that isn't bound by midpoints
Don't coredump the tests, just fail them
Know who your real dad is. [add a start* to the edge node]
WIP: edge search
Don't bother with v->poly lists at all, trust the index to clean it
Breaking up the edge_tree search
New  edge_tree_insert() and a fix to edge_tree_walk()
Guard against failing to generate a root
Free the endpoints of an edge when we free the startpoint
Might as well guard against null here, too
Merge pull request #40 from sshirokov/edge-as-point-and-tree

Don't use a midpoint sorted edge tree