The methods disconnect_points and are_points_connected now have an optional p_bidirectional parameter matching AStar.
(cherry picked from commit 3590cdfd34eea8dda746d7db1c7e5a79af389026)
Allow AStar/AStar2D zero point weight.
Limit was set to 1 which seemed like an arbitrary value as lower values down to zero can be useful for common gameplay navigation elements like teleports.
