Retracts all findings from node.

This includes positive findings (state and real value), negative findings, and likelihood findings. It removes them from any kind of node, including "constant" nodes.

If node does not have any findings, calling this will have no effect.

If the net is an auto-update net (see SetNetAutoUpdate_bn), then a belief updating will be done to reflect the removal of findings, before this function returns (otherwise it will just be done when needed). If you are going to be retracting a finding for a node, and then entering a new one, sometimes very significant performance gains can be made by ensuring auto-updating is turned off during the retraction (see example of EnterFinding_bn).